    [From the U.S. Government Printing Office, www.gpo.gov]

                    Coastal Zone
                    Information
                       Center

                                    Flood Hazard Potential of 18
                                                 Arctic Rivers in the
                          National Petroleum Reserve-Alaska

                                                                                                      COASTAL 7 N
                                                                                                                - @Q,, E
                                                                            by
                                                                                                INFORMATION CENTER
                                                                  Thomas W Mortensen

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                    1399.4
                    A4          odplain Studies Report No. 3
                    M65         --d for the North Slope Borough                    Volume          I                 January 1985
                    1985        lanagFment Program
                    V.

          NORTH SLOPE BOROUGH
          PLANNING DEPARTMENT

          P.O. Box 69
          Barrow, Alaska 99723

          Phone: (907) 852-2611          Earl L.. Finkler, Director

                May 30, 1986                                          lftorwpo red 1014

                Dear Reader:

                Because of your interest and involvement in activities on the
                North Slope I have enclosed for your information a copy of a
                recent Planning Department Publication entitled "Flood Hazard
                Potential of 18 Arctic Rivers in the National Petroleum Re-
                serve-Alaska". The objective of the report was to determine the
                potential flooding hazards of these rivers.

                This is the third report in a series on flood hazard potential of
                rivers within the North Slope Borough. To date 31 rivers have
                been mapped.' If you have questions or comments, or would like
                additional copies of this report or the previous two reports
                please contact Linda Okpik in the North Slope Borough Planning
                Department at the address listed above.

                Sincerely y

                Karla Kolash
                Deputy Director, Planning Dept.

                KK/bp

                enc

                          Flood Hazard Potential of 18
                                   Arctic Rivers in the
                    National Petroleum Reserve-Alaska

                                                      by

                                               Thomas W. Mortensen

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                                                Volume I

           40
                                            US Department of Commerce
                                        NOAA Coastal Services Center Library
                                             2234 South Hobson Avenue
                                             Charleston, SC 29405-2413

                     Maps contained in Volume 11 have been reduced as much as 60%.
                                Original mylars may be obtained from the
                      North Slope Borough, Planning Department for reproduction.

                                                                                         Abstract

                                                            The floodplains of 18 Arctic rivers in the Nationa I Petroleum Reserve-Alaska
                                                    were mapped in order to show their potential flooding hazards. The relative flooding
                                                    frequencies and an estimated frequency interval are tabled and compared for the 18
                                                    rivers of this study and the 13 rivers of two previous studies. Although the rivers of
                                                    Arctic Alaska are considerably different in most aspects from rivers of other climatic
                                                    regimens, similarities do exist between the Arctic rivers themselves. The flooding
                                                    units are characterized by distinct geomorphic and physiographic features. These
                                                    features can be correlated, in part, from one river system to another. The floodplain
                                                    geomorphology was interpreted by using a combination of Landsat satellite imagery
                                                    and the stereo viewing of both color infrared and black and white aerial photogra-
                                                    phy. Field verification of the relative flooding frequency and the geomorphic
                                                    description of each floodplain unit was accomplished in the summer of 1984. The
                                                    flooding potentials of each river were then mapped after the flooding parameter of
                                                    each geomorphic unit was determined. The 18 rivers that were mapped in this study
                                                    are the Ikpikpuk, Chipp, Alaktak, Miguakiak, Piasuk, Oumalik, Topagoruk, Meade,
                                                    Usuktuk, Ivisaruk, Kuk, Kaolak, Ketik, Avalik, Kugrua, Ongorakvik, Nokotlek and
                                                    the Tunalik. Potential gravel sources along five rivers were sampled and tested.

                                                            The Chipp, Topagoruk and Meade Rivers appear to be responding to tectonic
                                                    subsidence in the Dease Inlet/Admiralty Bay area. The active subsidence in this area
                                                    may explain the existence of the large embayment of Dease Inlet/Admiralty Bay into
                                                    the'Arctic Coastal Plain.

                                                                               TABLE OF CONTENTS

                                                  ABSTRACT     ......................................................                 i

                                                  LIST OF FIGURES    .................................................                v

                                                  LIST OF TABLES     ................................................                 viii

                                                  LIST OF MAPS   ...................................................                  ix

                                                  INTRODUCTION AND OBJECTIVES            ..................................           I

                                                  APPROACH AND METHODS OF MAPPING               .............................         3

                                                  LOCATION AND DESCRIPTION OF THE STUDY AREA                ....................      5

                                                  GEOLOGIC SETTING       ..............................................               7

                                                          Unconsolidated Late Cenozoic Deposits      .........................        7
                                                          Subsidence in the Admiralty Bay Area .    .........................         10
                                                  FLOOD FREQUENCY AND FLOODING POTENTIAL                  .....................       13
                                                          Maximum Flooding Potential     .................................            13
                                                          Flooding Potential of Arctic Rivers  .............................          13
                                                  SPRING BREAKUP CHARACTERISTICS OF THE ARCTIC RIVERS                  ...........    19

                                                  FLOODPLAIN GEOMORPHOLOGY AND FLOODING POTENTIAL OF THE
                                                          STUDY RIVERS      ...........................................               39

                                                  IKPIKPUK RIVER     ................................................                 39

                                                          Map Flood Units, Ikpikpuk River    ..............................           39
                                                  CHIPP RIVER    ...................................................                  45
                                                          Map Flood Units, Chipp River    ................................            45

                                                  ALAKTAK RIVER      ................................................                 55

                                                          Map Flood Units, Alaktak River    ...............................           55

                                                  MIGUAKIAK RIVER       ..............................................                57

                                                          Map Flood Units, Miguakiak River     .............................          57

                                                  PIASUK RIVER     ..................................................                 59

                                                          Map Flood Units, Piasuk River   ................................            59

                                                  OUMALIK RIVER      ..............      .................................            61

                                                          Map Flood Units, Ournalik River    .......................         ......   61
                                                  TOPAGORUK RIVER       ..............................................                63

                                                          Map Flood Units, Topagoruk River     .............................          63

                                                  MEADE RIVER      ..................................................                 65

                                                          Map Flood Units, Meade River    ................................            65

                   USUKTUK RIVER      ................................................           75

                           Map Flood Units, Usuktuk River   ..............................       75

                   IVISARUK RIVER     ................................................           77

                           Map Flood Units, Ivisaruk River ...............................       77

                   KUK RIVER     ....................................................            79

                           Map Flood Units, Kuk River  ..................................        79

                   KAOLAK RIVER     .........................         .......  I ............... 81
                           Map Flood Units, Kaolak River .................................       81

                   KETIK RIVER    ...................................................            83

                           Map Flood Units, Ketik River  .................................       83

                   AVALIK RIVER    ..................................................            85

                           Map Flood Units, Avalik River ................................        85

                   KUGRUA RIVER      .................................................           87

                           Map Flood Units, Kugrua River   ...............................       87

                   ONGORAKVIK RIVER        ..........  I....I .............................      89

                           Map Flood Units, -Ongorakvik River  ............................      89

                   NOKOTLEK RIVER      ...............................................           91

                           Map Flood Units, Nokotlek River  ..............................       91

                   TUNALIK RIVER ... .......................                             .....   @ @93

                           Map Flood Units, Tunalik River  ................................      93

                   SUMMARY OF CONCLUSIONS         ......................................         95

                   REFERENCES CITED       .............................................          97

                   APPENDIX A: List of Rivers Mapped   ..................................        99

                   APPENDIX B: Sources of Mapping Data     ..............................        101

                   APPENDIX C: River Channel Profile Data   .............................        113

                   APPENDIX D: Material Sites and Gradation Tests  ........................      117

                   APPENDIX E: Listof Map Units    .....................................         127

                   iv

                                                                                  LIST OF FIGURES

                                                  Text
                                                 Figures                                                                        PAGE

                                                     I     Location map of the study area   ...............................         2
                                                     2     Location map of the three Floodplain Study areas    .................    4
                                                     3     Physiographic provinces of the study areas    ......................     6
                                                     4     Generalized surficial deposits map   ............................        8
                                                     5     Landsat image; surficial deposits  ...............................       9
                                                     6     Infrared aerial photograph of the Meade River Delta    ...............   11
                                                     7     Comparison of flooding levels   ...............................          14
                                                     8     Landsat image, spring breakup (28 April 1984)  ..................        @20
                                                     9     Landsat image, spring breakup (28 April 1984)  ...................       21
                                                  10       Landsat image, spring breakup (I June 1984)   ....................       22
                                                  11       Map of the Barrow River Basin    ..............................          23
                                                  12       Landsat image, spring breakup (17 June 1984)   ...................       24
                                                  13       Landsat image, spring breakup (2 June 1984)   ....................       25
                                                  14       Oblique aerial photograph, Ikpikpuk River     .....................      26
                                                  15       Landsat image, before spring breakup (16 May 1981)    ..............     27
                                                  16       Landsat image, spring breakup (5 June 1979)   ....................       28

                                                  17       Landsat image, spring breakup on the Meade River Delta
                                                                   (5 June 1979) .......................................            29

                                                  18       Landsat image, spring breakup on the lkpikpuk River Delta
                                                                   (5 June 1979) ......................................             30
                                                  19       Landsat image, spring breakup on the Topagoruk River Delta
                                                                   (5 June 1979) .......................................            31
                                                  20       Oblique aerial photograph, spring breakup on the Topagoruk
                                                                   River Delta  .......................................             32

                                                  21       Landsat image, after spring breakup (12 July 1977)  ................     33
                                                  22       Landsat image, lkpikpuk River Delta (12 July 1977)   ...............     34
                                                  23       Landsat image, lkpikpuk River (12 July 1977)  ....................       35
                                                  24       Landsat image, Kuk River (2 May 1979)    ........................        36
                                                  25       Landsat image, spring breakup on the Kuk River (13 June 1979)    ......  37
                                                  26       Infrared aerial photograph of the Ikpikpuk River Delta  ......       ... 41

                                                                                                                                     v

                  27       Oblique aerial photograph, storm surge debris on the
                                   Ikpik-puk River Delta   ................................          42
                  28       Photograph, lkpikpuk River abandoned channel       .................      43
                  29       Oblique aerial photograph, Chipp River     .......................        46
                  30       Infrared aerial photograph, Chipp River talik lake breach    ..........   47
                  31       Black and white aerial photograph, Chipp River talik lake breach      .... 48
                  32       Oblique aerial photograph, Chipp River talik lake breach      ..........  49
                  33       Landsat image, Chipp, River talik lake breach (5 June 1979)   .........   50
                  34       Landsat image, Chipp River talik lake breach (12 July 1977)   .........   51
                  35       Infrared aerial photograph, Chipp River    .......................        52
                  36       Black and white aerial photograph, Chipp River breached lake      ......  53
                  37       Oblique aerial photograph, Miguakiak River      ....................      58
                  38       Infrared aerial photograph, Topagoruk River Delta      ...............    64
                  39       Oblique aerial photograph, spring breakup on the Meade River      ......  66
                  40       Oblique aerial photograph, ice jam on the Meade River      ............   67
                  41       Oblique aerial photograph, ice jam on the Meade River      ............   68
                  42       Black and white aerial photograph, Meade River     .................      69
                  43       Oblique aerial photograph, Meade River     .......................        70
                  44       Oblique aerial photograph, Meade River     .......................        71
                  45       Photograph, Meade River flooding evidence       ....................      72
                  46       Oblique aerial photograph, Meade River bedrock       ................     73
                  47       Oblique aerial photograph, Meade River bedrock     .................      74
                  48       Oblique aerial photograph, Chukchi Sea storm surge strandline     ......  80
                  49       Gradient profiles of 15 Arctic rivers  .....................      in pocket
                  50       Gradient profiles of lkpikpuk River and distributaries   ........ in pocket
                  51       Gradient profiles of Kuk River and tributaries   ..............   in pocket

                 Appendix
                Figures                                                                           PAGE

                   D-1     Photograph of lkpikpuk Active Channel Material Sample site
                                   (A.C.M.S.) No. I of Map Ic    ..........................          118
                   D-2     Photograph of Ikpikpuk Active Channel Material Sample site
                                   (A.C.M.S.) No. 2 of Map Ic    ..........................          119

               vi

                                                   D-3     Photograph of Topagoruk Active Channel Material Sample site
                                                                   (A.C.M.S.) No. I of Map lb  ..........................       120
                                                   D-4     Photograph of Meade Active Channel Material Sample site
                                                                   (A.C.M.S.) No. I of Map 2b  ..........................       121
                                                   D-5     Photograph of Meade Active Channel Material Sample site
                                                                   (A.C.M.S.) No. 2 of Map 2b  .............    :.......    .... 122
                                                   D-6     Photograph of Ivisaruk Active Channel Material Sample site
                                                                   (A.C.M.S.) No. I of Map 4b  ..........................       123
                                                   D-7     Photograph of Material Site (M.S.) No. I of Map 5  ...............   125
                                                   D-8     Photograph of Material Site (M.S.) No. I of Map 5  ...............   126

                                                                                                                                Vii

                                                       LIST OF TABLES

                   Text
                   Tables                                                                             PAG E

                       I    Stream gradient characteristics of 29 Arctic Rivers    .................      15
                       2    29 Arctic rivers arranged in order of increasing gradient     ............    16

                       3    29 Arctic rivers arranged in order of decreasing area
                                     of waters hed   ........................................             17

                       4    A tentative flood frequency interval and comparison of
                                     flooding units for the 18 rivers of this investigation  ..........   18
                       5    A tentative flood frequency interval and comparison of
                                     flooding units for the 8 Arctic rivers of Cannon, 1983     ........  18
                       6    A tentative flood frequency interval and comparison of
                                     flooding units for the 5 Arctic rivers of Mortensen and
                                     Cannon, 1982 (from Cannon, 1983)         ........    ............    18
                       7    General geomorphic river channel characteristics of 31
                                     Arctic rivers    ......................................              40

                   Viii

                                                                     LIST OF MAPS

                                       Map Index Map of Rivers, National Petroleum Reserve-Alaska

                                         la   Flood Hazard Potential of the lkpikpuk, Chipp, Alaktak, Miguakiak,
                                                      Piasuk and Topagoruk Rivers; National Petroleum
                                                      Reserve-Alaska

                                         Ib   Flood Hazard Potential of the lkpikpuk, Chipp, Oumalik and Topagoruk
                                                      Rivers; National Petroleum Reserve-Alaska

                                         Ic   Flood Hazard Potential of the lkpikpuk River; National Petroleum
                                                      Reserve-Alaska

                                         I d  Flood Hazard Potential of the Ikpikpuk River; National Petroleum
                                                      Reserve-Alaska

                                         2a   Flood Hazard Potential of the Meade and Usuktuk Rivers; National
                                                      Petroleum Reserve-Alaska

                                         2b   Flood Hazard Potential of the Meade and Usuktuk Rivers; National
                                                      Petroleum Reserve-Alaska

                                         2c   Flood Hazard Potential of the Meade River; National Petroleum
                                                      Reserve-Alaska

                                         3    Flood Hazard Potential of the Kugrua River; National Petroleum
                                                      Reserve-Alaska

                                         4a   Flood Hazard Potential of the Kuk and Ivisaruk Rivers; National
                                                      Petroleum Reserve-Alaska

                                         4b   Flood Hazard Potential of the Kuk, 1-@isaruk and Kaolak Rivers; National
                                                      Petroleum Reserve-Alaska

                                         4c   Flood Hazard Potential of the Avalik and Ketik Rivers; National
                                                      Petroleum Reserve-Alaska

                                         4d   Flood Hazard Potential of the Ketik River; National Petroleum
                                                      Reserve-Alaska

                                         5    Flood Hazard Potential of the Tunalik, Ongorakvik and Nokotlek Rivers;
                                                      National Petroleum Reserve-Alaska

                                                                                                                             ix

                                                    Introduction and Objectives.

                                                             The major objective of this study was to map at a scale of 1:63,360 the extent
                                                    of the active and inactive floodplains of 18 Arctic rivers along the Chukchi Sea and
                                                    Beaufort Sea Coasts within the National Petroleum Reserve-Alaska (formerly Naval
                                                    Petroleum Reserve No. 4) (Figure 1). Other objectives were to establish relative and
                                                    estimated flooding frequencies (Table 4) and potential flooding hazards. The 18
                                                    rivers are:
                                                                      lkpikpuk River                     lvisaruk River
                                                                        Chipp River                        Kuk Rivet
                                                                       Alaktak River                      Kaolak River
                                                                     Miguakiak River                       Ketik River
                                                                       Piasuk River                       Avalik River
                                                                      Oumalik River                    Ongorakvik River
                                                                     Topagoruk River                     Nokotlek River
                                                                       Meade River                        Kugrua River
                                                                      Usuktuk River                       Tunalik River
                                                             Fourteen maps were produced by this study. The first map (Unnumbered) is
                                                    an index map showing the location of the rivers and areas mapped as part of this
                                                    study. Map I a shows the floodplains and flood hazard potential of the lkpikpuk,
                                                    Chipp, Alaktak, Miguakiak, Piasuk and Topagoruk Rivers. Map lb shows the
                                                    floodplains and flood hazard potential of the lkpikpuk, Chipp, Ournalik and
                                                    Topagoruk Rivers. Map I c shows the floodplain and flood hazard potential of the
                                                    lkpikpuk River. Map ld shows the floodplain and flood hazard potential of the
                                                    lkpikpuk River. Map 2a shows the floodplains and flood hazard potential of the
                                                    Meade and Usuktuk Rivers. Map 2b shows the floodplains and flood hazard potential
                                                    of the Meade and Usuktuk Rivers. Map 2c shows the floodplain and flood hazard
                                                    potential of the Meade River. Map 3 shows the floodplain and flood hazard of the
                                                    Kugrua River. Map 4a shows the floodplains and flood hazard potential of the Kuk
                                                    and lvisaruk Rivers. Map 4b shows the floodplains and flood hazard potential of the
                                                    Kuk, lvisaruk and Kaolak Rivers. Map 4c shows the floodplains and flood hazard
                                                    potential of the Avalik and Ketik Rivers. Map 4d shows the floodplain and flood
                                                    hazard of the Ketik River. Map 5 shows the floodplains and flood hazard potential of
                                                    the Tunalik, Ongorakvik and Nokotlek Rivers.
                                                             The maps provide information which can be used to delineate the following:
                                                             I .active floodplains
                                                             2. standard project floodplains
                                                             3. abandoned or inactive floodplains
                                                             4. active channels
                                                             5. the estimated relative flood frequency and flood magnitude for each
                                                               mapping unit
                                                             6. areas of major flooding hazards
                                                             7. related non-floodplain geomorphic features and generalized terrain units

                                                                                                                                           1

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                         Figure     1.
                         Location map of the study area.                    Scale;     1:2,500,000.

                         2

                                                   Approach and Methods of             Mapping

                                                            This study is a continuation of two similar studies performed on the
                                                   Colville, Kuparuk, Sagavanirktok, Shaviovik and Canning,Rivers (,Mortensen and
                                                   Cannon, 1982), and the Avak, Utukok, Kokolik, Epizetka, Kukpowruk, Pitmegea,
                                                   Ipewik and Kukpuk Rivers (Cannon, 1983) (Figure 2). The approach used to map the
                                                   floodplains of this study and the previous two studies is considered the classic
                                                   approach to mapping. This approach employs the use of aerial photographs and field
                                                   work. However, this study was greatly augmented by the use of modern remote
                                                   sensing data such as false color infrared aerial photographs and Landsat satellite
                                                   imagery.
                                                            The basic geomorphic information about the floodplains was interpreted
                                                   from Landsat satellite imagery and the stereo viewing of both color infrared and
                                                   black and white aerial photography (Appendix 13). The various geomorphic features
                                                   which indicate specific floodplain physiographic units and hence topographic levels
                                                   relative to the.active channel were identified and mapped at the scale of the aerial
                                                   photographs. These features were then field checked and mapped as flood or non-
                                                   flood units on a preliminary base map at a scale of 1:63,360. The units were
                                                   rechecked and then transferred to a final map base on mylar at a scale of 1:63,360.
                                                   The combination of interpretating the floodplain geomorphology and field work is a
                                                   relatively fast and accurate technique of mapping a river's flood hazard potential
                                                   (Wolman, 1971). This technique is also applicable to Arctic rivers, provided that the
                                                   possible changes of the geomorphology/flooding relationships along a particular
                                                   drainage are considered (Mortensen, 1982).
                                                            Low altitude aerial reconnaissance of the rivers was performed in earlyjune
                                                   to observe and photograph the magnitude of flooding during spring breakup. The
                                                   main part of the field work was performed during late July and early August. A Bell
                                                   206 helicopter was used for acquiring very low altitude aerial photography of the
                                                   floodplain geomorphic units. The use of a helicopter also made it possible to make
                                                   ground observations of flooding evidence and measurements at specific locations
                                                   selected from the preliminary floodplain mapping.
                                                            The observed ground evidence of flooding includes:
                                                            1. Presence of silts, sands, and gravels that have recently undergone active
                                                              water transport.
                                                            2. Driftwood and debris, especially when found on tundra covered flood-
                                                              plain units (Figures 44 and 45).
                                                            3. Fine sand/silt layers on tundra covered floodplain units.
                                                            4. Water scour of the tundra covered floodplain units (Figures 44 and 45).

                                                                                                                                        3

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                            Figure 2.
                            Location map of the three Floodplain Study areas.

                            4

                                                    Location and Description of the Study Area

                                                            The area of this investigation includes the land along the Chukchi Sea Coast
                                                    from Icy Cape to Point Franklin, and along the Beaufort Sea Coast from Admiralty
                                                    Bay to Smith Bay (Figures I and 2). This area is the extreme northern part of Alaska,
                                                    and is entirely above the Arctic Circle. The study area is part of two previously
                                                    mapped physiographic divisions (Wahrhaftig, 1965). The northern region is part of
                                                    the Teshekpuk section of the Arctic Coastal Plain province. The southern region of
                                                    the study area is part of the northern section of the Arctic Foothills province
                                                    (Figure 3).
                                                             The 13 rivers of this study that lie completely or mostly within the limits of
                                                    the flat and poorly drained Teshekpuk section of the Arctic Coastal Plain province
                                                    are the Miguakiak, Piasuk, Alaktak, Chipp, Ournalik, Topagoruk, Usuktuk, Kugrua,
                                                    Kuk, Ivisaruk, Ongorakvik, Nokotlek and the Tunalik. The lower parts of the
                                                    Ikpikpuk and Meade Rivers lie within the Arctic Coastal Plain province, while large
                                                    sections of their upper drainages are within the northern section of the Arctic
                                                    Foothills province. The only rivers of this study that have their watersheds
                                                    completely within the northern section of the Arctic Foothills province are the
                                                    Kaolak, Ketik and the Avalik. This northern section rises from an altitude of 600 feet
                                                    on the north to a maximum elevation of 1541 feet within the Meade River watershed.
                                                    It has broad east-west trending ridges, that are dominated by mesa-like mountains.
                                                    The average maximum elevation in this section is approximately 1,000 feet in the
                                                    Meade, Ikpikpuk and Ketik drainages, 500 feet in the Avalik and 300 feet in the
                                                    Kaolak watershed.
                                                            For a detailed description of the mapping of each river's floodplain, refer to
                                                    Appendix A.

                                                                                                                                          5

                                                              162'                                           160,                                           158'                                           156'                                           154'                                        152'

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                                       Figure          3.
                                        Physiographic provinces of the study area.

                                        6

                                                     Geologic Setting

                                                              The geology of the area of this investigation indicates a tremendous
                                                     potential for economic resources in the manner of petroleum products. The
                                                     Teshekpuk section of the Arctic Coastal Plain province is composed of broad folded
                                                     structures which are ideal petroleum reservoirs. The northern section of the Arctic
                                                     Foothills province is a transition zone, where the broad folds give way to tighter folds
                                                     and strong faulting. The southern section of the Arctic Foothills province is
                                                     predominantly south of this transition zone. This southern section consists of
                                                     intensely thrust faulted rocks and complex structures.
                                                              The bedrock underlying most of the study area is sedimentary sandstone,
                                                     shale, clay, bentonitic clay, silty shale and coal of the Cretaceous in age Nanushuk
                                                     Group. It is exposed in the southern part of the northern section of the Arctic
                                                     Foothills physiographic province, in several places along the bluffs of the Chukchi
                                                     Sea Coast, and in places along many of the rivers of this study. The Nanushuk Group
                                                     rocks are covered by a mantle of unconsolidated late Cenozoic marine, lacustrine,
                                                     alluvial and eolian deposits in the northern part of the northern section of the Arctic
                                                     Foothills physiographic province, and in the Arctic Coastal Plain physiographic
                                                     province.

                                                              Unconsolidated Late Cenozoic Deposits
                                                              The most recent studies of the surficial geology in the area of this
                                                     investigation have been done by Williams and others (1977), Williams (1983a and
                                                     1983b), Carter (1983), and Yeend (1983).
                                                              Upland silt: Deposits of silt, silty sand and fine sand with locally scattered
                                                     pebbles. Stratification is indistinct. Well sorted and calcareous. The deposits are
                                                     largely wind-blown silt or silt retransported by running water. Contains ice wedges
                                                     and a very high volume of ice as small interstitial grains, masses and lenses in some
                                                     areas approaching 80 percent of the volume of the subsurface materials. This deposit
                                                     occurs along the northern edge of the northern section of the Arctic Foothills
                                                     physiographic province and ends at an abrupt 50-200 foot high scarp, that may be
                                                     tectonic in origin, at the Arctic Coastal Plain province boundary (Figure 4 and 5).
                                                              Sandy retransported deposits: Deposits of fine to medium, well sorted
                                                     eolian sand that has been retransported by running water. This deposit overlies older
                                                     marine and other unconsolidated deposits. Its thickness ranges from 18 to 30 meters.
                                                     In the mapping area of this study these deposits occur upstream of the junction of the
                                                     lkpikpuk and Price Rivers.
                                                              Eolian sand: Deposits of fine wind-blown sand containing abundant quartz
                                                     and minor dark minerals. Well sorted and stratified, with large scale cross-bedding in
                                                     places. This deposit often contains peat beds and wood in the upper few meters. This
                                                     eolian sand deposit forms a large sand sea that is Pleistocene in age and extends from
                                                     the Colville River on the east to just west of the Meade River near Atkasook. The
                                                     dunes have been modified by younger eolian activity and thermokarst processes.
                                                     This is the most extensive area of large stabilized dunes yet reported in the North
                                                     American Arctic (Carter, 1981).
                                                              Marine sand: A deposit of predominantly silty sand with scattered pebbles. It
                                                     ranges from four to six meters thick and overlies marine silt and clay deposits of
                                                     undetermined thickness. This deposit forms residual surfaces between thaw lake

                                                                                                                                             7

                          basins on the Arctic Coastal Plain. This deposit forms the northern boundary of the
                          eolian sand sea in the Ikpikpuk and Meade Rivers area.
                                     Elevated marine deposits: These deposits are marine beach, offshore bar and
                          barrier islands related to the Pelukian aged shoreline when sea level was as much as
                          20 meters higher than at present, and pre-Illionian or Kotzebuan aged shoreline
                          when sea level was 20 to 30 meters higher than at present. The Pelukian deposits
                          occur along the north shore of Teshekpuk Lake, in the Admiralty Bav area to Barrow,
                          in the Peard Bay area near the Kugrua River and along the Chukchi Sea Coast
                          northeast of icy Cape. The Kotzebuan deposits occur along the Chukchi Sea Coast
                          northeast of Icy Cape, inland from the Pelukian deposits.
                                     Thaw-lake deposits: These are localized and thin deposits that consist of
                          sediment eroded from lake banks and redistributed by currents and wave action.
                          They contain retransported pieces of peat as well as in situ peat beds and lenses.
                          These silty and organic rich deposits are exposed when the thaw-lake basin drains.
                                          1624                     1600              __1500                         1560                    1540                    1520
                                                                     1                           l1t.
                                                                                                 Barrow                   Admiralty
                                                                                                                              Bav
                                                                      Cape
                                                                      Franklin

                                                                                                                                                Z Z
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                                Cape                                                                                                        Teshekpuk
                                                                                                                             A7.                Lake

                                                                                                                      CIO. -
                    706                                                                                                                         ..... ............
                                                                                                                                              ................... ..
                                                                                                                                              . . . . . . . . . . . . . . .
                                                                                                                                              . . . . . . . . . . . .
                                        K       X                  x  V x                                                                     - - - - - - - ---- - -
                                                                                                                                         - - - - - - - - - - - -
                                         A   U    AN                                                                                  77 - - - - - - - - - - - - -
                                                                                         J.-                                                    - - - - - - - - - - - --
                                                                                            xxx     xxxp N A         P ft     ..     a ?F, .  ..'_ _.
                                         19 x                                                            N"A"A VOXN
                                        V                                                                XN x x

                                                                                                                                                     x
                                                        0                        50                                                                            NY

                                                               Kilometers
                                                                                                                                                             C'ek";

                                    Beach deposits                   A11UViUm                      Nlarine silt                 Marine sand                Folian sand
                                                                                   1. x X R                                                         (rUled where reworked
                                                                                      x x x j                                                              by streams)
                                                                                   Upland silt               )VaIT-CLA shoreline
                                                                                                            hachures do%,,,nslope

                          Figure 4.
                          Generalized surficial deposits map of the National Petroleum Reserve-Alaska.
                          Modified from Williams, 1978.

                          .8

                                                            Alluvial deposits: Stratified to lenticular deposits of sand, silt and some
                                                   gravel in the upper river drainages, generally becoming finer downstream. Gravel is
                                                   subrounded to angular, depending on the source in marine deposits, fluvial gravel or

                                                                                                                                     A

                                                                                                                                 -F

                AV

                                                                                                                              PT
                                                                                                                       7'

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              51
                        Wvni

                                                             Figure 5.
                                                             Landsat image E-30367-21404-7 (7 March 197 9)
                                                             Generalized SUrficial deposits of part of the National Petroleum Reserve-Alaska.

                                                                                                                                       9

                   in broken and weathered bedrock. Silt and organic beds are common in all types of
                   alluvium, particularIN, as overbank deposits on active and inactive floodplain
                   Surfaces.

                            Subsidence in the Admiralty Bay Area
                            The Mapping of the floodplains of the major rivers of the National
                   Petroleum Reserve-Alaska at the detail necessary to produce the flood hazard maps of
                   this investigation, has revealed recent changes in some of the rivers' drainage
                   patterns. These changes may reflect tectonic influences on the rivers. The Meade,
                   Topagoruk and Chipp Rivers flow into Admiralty Bay. All three of these rivers appear
                   to be responding to active subsidence in the Dease Inlet/Admiralty Bay area.
                            The direction of the channel of the Topagoruk River below the 50 foot
                   topographic contour (Maps la and 1b) has shifted from a northeast direction of flow
                   toward the present channel of the Chipp River, to a north northeast direction, and
                   then to its present active channel which flows due north toward, and then west into
                   Admiralty Bay.
                            The Chipp River below the 50 foot topographic contour (Maps la and lb)
                   appears to be shifting its channel to the west through the process of talik lake
                   breaching. This process is where the active river channel breaches one or a series of
                   talik lakes that are adjacent to the river channel, drains them and forms a new channel
                   through the drained takes. Aerial photographic evidence shows that the most recent
                   talik take breaching of the Chipp River has occurred within the last 35 years (see
                   Figures 30 to 34).
                            The Meade River (Maps 2a and 2b) flows in a northward direction across the
                   Arctic Coastal Plain from its headwaters in the Arctic Foothills until six miles
                   downstream (north) of the village of Atkasook where it makes an abrupt turn to the
                   northeast and flows into Admiralty Bay
                            The Arctic Coastal Plain that these rivers flow across is very flat. Thus, the
                   rivers may be expected to respond to even a small local change in the carth's crust. All
                   three of these major Arctic rivers appear to be responding to tectonic subsidence in
                   the Dease Inlet/Admiralty Bay area. The active subsidence in this area may explain the
                   existence of the large embayment of Dease Inlet/Admiralty Bay into the Arctic Coastal
                   Plain (Figure 16).
                            This theory of subsidence is further supported by a 30-year period of aerial
                   photographic data. A comparison of aerial photographs taken of the Meade River
                   Delta in 1949 and 1979 shows that the delta front is neither prograding or stable, but
                   is in fact receding slowly (Figure 6). This is unexpected for a large river like the
                   Meade, which should be supplying its delta with enough material to keep it growing,
                   or at least stable, in a relatively protected area like Admiralty Bay.
                            In comparison to the Meade, the Chipp River has virtually no delta, and the
                   Topagoruk River has an anomalously small delta in comparison to its drainage basin
                   (see Figures 35 and 38).
                            An alternative explanation to tectonic subsidence is the local subsidence in
                   Admiralty Bay due to the loss of ground ice. This process would adequately explain
                   the receding delta of the Meade River and the anomalously small deltas of the Chipp
                   and Topagoruk Rivers. However the localized subsidence due to the loss of ground
                   ice does not seem adequate to explain the observed behaviour of the channels of the
                   three rivers.

                   10

                                                   ..............

                                                                                              r   @AA

                                                                                               TIM

                                                     Figure 6.
                                                     A NASA high altitude aerial photograph of part of the Meade River Delta (the black areas are
                                                     water). The delta front is neither prograding (growing) nor stable, but is receding slowly.
                                                     Notice that the delta (left) lacks deposits of sand and silt at the channel mouths. Compare
                                                     this photograph to Figure 26 of the lkpikpuk River Delta which is an actively prograding
                                                     delta. The scene is 15 km. (9 mi.) across. Roll 2790, frame number 3098, July 1979.

                                                      Flood Frequency and Flooding Potential

                                                               The magnitude and frequency of flooding may be predicted where suffic-
                                                      ient discharge data for a river exists. For a particular river, the flood of the greatest
                                                      recorded discharge is designated as number one, the flood of the second greatest
                                                      discharge as number two, etc. Since there may be more than one flood of a given
                                                      discharge, a flood recurrence interval (RI) is calculated:

                                                                                                  N - I
                                                                                             Rl@ M
                                                      where N is the number of years that a flood of a given discharge recurs, and M is the
                                                      number assigned in listing flood discharge.
                                                               The recurrence interval is the number of years, on the average, until a given
                                                      flood will be equaled or exceeded one time. It is inversely relatcd to the probabilitN,
                                                      that a given flood will be equaled or exceeded in any one year. (A 25-year flood would
                                                      have one chance in 25, or a 50-year flood one chance in 50 of being equaled or
                                                      exceeded in any one year.)
                                                               The data may be extrapolated to predict a flood magnitude with a
                                                      recurrence interval that is greater than the length of continuous records.
                                                               Predicting flood frequency and discharge magnitudes by this method is not
                                                      applicable to the Arctic rivers of this study, because of the lack of recorded flooding
                                                      data.

                                                               Maximum Flooding Potential
                                                               The intermediate regional flood is defined as a flood at any given location
                                                      having an average frequency or recurrence interval of once in 100' years. It is less
                                                      severe than the standard project flood (Figure 7/1) (Leopold, 1978). This flood stage
                                                      will probably cover the lower areas of flood unit 4 (Table 4) that are closest to the
                                                      active channel.
                                                               The standard project flood is defined as the largest flood that can be
                                                      experienced from the most severe combinations of meteorological and hydrological
                                                      conditions that are considered reasonably characteristic of the geographical region
                                                      involved. Estimates indicate that the standard project flood discharges are generalIN
                                                      equal to 40 to 60 percent of the maximum probable floods for the same basins (Ven Te
                                                      Cho-,v, 1964). The standard project flood will probablv cover all of flood unit 4.
                                                               The maximum probable (or maximum possible) flood is defined as the flood
                                                      discharges that may be expected from the most severe combination of critical
                                                      meteorologic and hydrologic conditions that are reasonablv possible in the region
                                                      (Ven Te Chow, 1964). If a maximum probable flood were to occur on the rivers of this
                                                      investigation it will cover all of flood unit 4 and may even inundate some of flood unit
                                                      5 (which is designated a non-flooding unit). This is because the maps of this StUdy
                                                      were done under the assumption that the standard project flood was the maxii-nurn
                                                      reasonable discharge that the study rivers could produce.

                                                               Flooding Potential of Arctic Rivers
                                                               The discharge of a river is equal to the total arnount of effective precipitation
                                                      that falls on the watershed minus the amounts of infiltration, evaporation and
                                                      transporation. In warmer climates the discharge will be 15 to 46 percent of the total
                                                      effective precipitation. However in the Arctic this is much different. Because the
                                                      ground is frozen, there is almost no infiltration into it. The cooler climate decreases

                                                                                                                                              13

                    500                                                            V

                    480

                  -U                 Standard
                  .0                   Project
                                        Flood
                  > 460

                    440                                        Intermediate
                                                               Regional Flood (100 yr)

                                                   500 fcct

                  Figure 7.
                  General comparison of the intermediate regional flood to the standard project flood.

                  the amount of water evaporated back into the atmosphere, and the type of vegetation
                  that is in the Arctic would transpire only small amounts of water. From two studies
                  done on the hydrologic effects of frozen ground in the tundra zone of the Northern
                  U.S.S.R., the amount of runoff ranged from 70 to 76 percent of the total effective
                  precipitation (Dingman, 1975).
                          Since an Arctic river would only have a time window for flowing of four or
                  five months, the mean rate of discharge would be greater for the Arctic river than for
                  a more temperate river. The rivers of this investigation have the majority of their
                  discharge occurring within the first two weeks after the spring breakup. It seems
                  possible, therefore, that certain flooding events would have a greater frequency of
                  occurrence on the Arctic rivers than on rivers of warmer climates. An estimated
                  range of flooding frequency in years is presented in Table 4 for the various flooding
                  units of the 18 Arctic rivers of this investigation. These are tentative estimates based
                  on limited data and observations. They will undoubtedly be revised with future
                  observations and study.

                  14

                                                                 Table 1. Stream Gradient Characteristics of the 29 Arctic Rivers

                                                                                 Channel Length           Gradient (feet          Elevation of
                                                       Rivers                   Measured (miles)            per mile)            Channel (feet)
                                                       (This Investigation)
                                                       Usuktuk                           97.0                    0.3                    50
                                                       Ournalik                          40.0                    0.5                    75
                                                       Alaktak                           43.5                    0.6                    25
                                                       Chipp                             62.0                    0.9                    57
                                                       Kuk/Avalik                      104.9                     0.9                    98
                                                       Topagoruk                       101.5                     1.0                   100
                                                       lkpikpuk                        181.3                     1.2                   213
                                                       Meade                           150.4                     1.3                   200
                                                       Ketik                             60.8                    1.6                    98
                                                       li,isaruk                         56.0                    1.8                   100
                                                       Kugrua                            39.0                    1.9                    75
                                                       Kaolak                            43.7                    2.3                    98
                                                       Nokotlek                          18.0                    2.8                    50
                                                       Tunalik                           27.5                    3.6                   100
                                                       Ongorakvik                        16.5                    6.1                   100

                                                       (Cannon,1983)

                                                       Kokolik                         110.5                     2.7                   300
                                                       Utukok                            95.4                    3.1                   300
                                                       Epizetka                          46.7                    3.2                   150
                                                       Avak                              59.2                    3.4                   200
                                                       Kukpuk                          103.0                     3.9                   4oo
                                                       Kukpowruk                         62.2                    5.6                   350
                                                       lpewik                            45.2                    5.9                   250
                                                       Pitmegea                          40.7                    8.6                   350

                                                       (Mortensen and Cannon, 1981)

                                                       Colville                        134.0                     2.3                   300
                                                       Kuparuk                           82.0                    3.1                   250
                                                       Sagavanirktok                     56.0                    6.3                   350
                                                       Shaviovik                         40.0                    6.9                   275
                                                       Canning                           34.5                    10.1                  350

                                                                                                                                                  15

                           Table 2. The 29 Arctic Rivers Arranged in Order of Increasing Gradient

                     Rivers                                  Gradient in Feet Per Mile

                     UsuktUk                                                  0.3                  Lowest Gradient
                     Ourrialik                                                0.5
                     Alaktak                                                  0.6
                     Chipp                                                    ().9
                     Kuk/Avalik                                               0.9
                     Topagoruk                                                1.0
                     lkpikpuk                                                 1.2
                     Meade                                                    1.3
                     Ketik                                                    1.6
                     Ivisaruk                                                 1.8
                     Kugrua                                                   1.9
                     Kaolak                                                   2.3
                     Colville                                                 2.3
                     Kokolik                                                  2.7,
                     Nokotlek                                                 2.8
                     Kuparuk                                                  3. 1
                     Utukok                                                   3.1
                     Epizetka                                                 3.2
                     Avak                                                     3.4
                     Tunalik                                                  3.6
                     Kukpuk                                                   3.9
                     Kukpowruk                                                5.6
                     lpewik                                                   5.9
                     Ongorakvik                                               6. 1
                     Sagavanirktok                                            6.3
                     Shaviovik                                                6.9
                     Pitmegea                                                 8.6
                     Canning                                                  10.1                 Highest Gradient

                     l.6

                                                          Table 3. The 29 Arctic Rivers Arranged in Order of Decreasing Area Watershed

                                                         Rivers                                                Area of Watershed (square miles)
                                                         Colville (1)                                                          17,344.0
                                                         Ikpikpuk (2)                                                          4,488.0
                                                         Kuk (3)                                                               4,275.0
                                                         Meade (3)                                                             3,885.0
                                                         Sagavanirktok (1)                                                     3,566.0
                                                         Kuparuk                                                               2,673.0
                                                         Utukok                                                                2,278.0
                                                         Kokolik                                                               1.746.0
                                                         Kukpuk(4)                                                             1,690.0
                                                         Canning (1)                                                           1,485.0
                                                         Chipp/Ournalik                                                        1,475.0
                                                         Kukpowruk                                                             1,360.0
                                                         Shaviovik                                                             1,254.0
                                                         Avalik                                                                1,197.0
                                                         Ipewik                                                                  870.0
                                                         Topagoruk                                                               783.0
                                                         Kaolak                                                                  736.0
                                                         Ketik                                                                   721.0
                                                         Usuktuk                                                                 622.0
                                                         Ivisaruk                                                                522.0
                                                         Pitmegea                                                                433.0
                                                         Epizetka                                                                366.0
                                                         Kugrua                                                                  318.0
                                                         Avak                                                                    282.0
                                                         Tunalik                                                                 145.0
                                                         Nokotlet                                                                105.0
                                                         Ongorakvik                                                                73.0
                                                         Alaktak (5)                                                                N/A

                                                         I Does not include large area of delta.
                                                         2 Does not include distributary channels or delta.
                                                         3 Includes the Avalik, Kaolak, Ketik and Ivisaruk Rivers.
                                                         4 Includes the lpewik River.
                                                         5 Distributary channel of the Ikpikpuk River.

                                                                                                                                                        17

                  Table 4. A Tentative Flood Frequency Interval and Comparison of Flooding Units
                             for the 18 Arctic Rivers of This Investigation.

                                            Estimated Flood Frequency in Years

                  River           Flooding Units=        1              2                3             4
                  IkPikpuk                               1            3-10           10-50          100-200
                  Chipp                                  1            3-10           10-50          100-200
                  Alaktak                                1            3-10           10-50          100-200
                  Miguakiak                              1            3-10           10-50          100-200
                  Piasuk                                 I            N/A            10-50          100-200
                  Oumalik                                1            3-10           10-50          100-200
                  Topagoruk                              1            3-10           10-50          100-200
                  Meade                                  1              3-7              7-25         50-100
                  Usuktuk                                1            3-10           10-50            50-100
                  Ivisaruk                               1            3-10           25-50            50-100
                  Kuk                                    1            3-10           10-25            50-100
                  Kaolak                                 1            3-10           10-25            50-100
                  Ketik                                  1            3-10           10-25            50-100
                  Avalik                                 1            3-10           10-25            50-100
                  Ongorakvik                             1              3-7              5-50         N/A
                  Nokotlek                               1              3-7              5-50         N/A
                  Kugrua                                 1              3-7              5-50         N/A
                  Tunalik                                1              3-7              5-50         N/A

                  Table 5. A Tentative Flood Frequency Interval and Comparison of Flooding Units
                             for the 8 Arctic Rivers of Cannon, 1983.

                                            Estimated Flood Frequency in Years

                  River Flooding Units=          1             2            3              4             5
                  Avak                           1            3-7          5-50          N /A          N/A
                  Utukok                         1            3-7          5-50          25-100        N/A
                  Kokolik                        1            3-77         5-50          25-100        N/A
                  Epizetka                       1            3-7          5-50          25-100        N/A
                  Kukpowruk                      1            3-7          5-50          25-100       75-500
                  Pitmegea                       1            3-7          5-50          N/A           N/A
                  1pewik                         1            3-7          5-50          25-100        N/A
                  Kukpuk                         1            3 -71        5-50          25-100        N/A

                  Table 6. A Tentative Flood Frequency Interval and Comparison of Flooding Units
                             for the 5 Arctic Rivers of Mortensen and Cannon, 1982
                             (from Cannon, 1983)

                                           Estimated Flood Frequency in Years

                  River      Flooding Units =      FI              F2                F3               F4
                  Colville                         1               3-7              5-50            25-100
                  Kuparuk                          1               3-7              5-50            25-100
                  Sagavanirktok                    1               3-7              5-50            25-100
                  Shaviovik                        1               3-7              5-50            25-100
                  Canning                          1               3-7              5-50            25-100

                  18

                                                       Spring Breakup Characteristics of the Arctic Rivers

                                                                Observations of Landsat imagery at the breakup period for the 18 rivers of
                                                       this study indicate that breakup occurs during late May to earlyjune. This is a week or
                                                       more later than the breakup on all but one of the rivers (the Avak River, Floodplain
                                                       Study No. 2) of the previous two North Slope Borough Floodplain Studies (Morten-
                                                       sen and Cannon, 1982 and Cannon, 1983). This observed difference of river breakup
                                                       timing can be explained by the fact that all of the river drainages of this study, and the
                                                       Avak River, have watersheds that are restricted to the Arctic Coastal Plain and the
                                                       northern section of the Arctic Foothills physiographic provinces (Figure 3). The
                                                       rivers of the previous two studies have their headwaters in the Brooks Range, where
                                                       the winter snowpack usually begins to melt and supply the river channels with water
                                                       before the snowpack begins to melt on the Arctic Coastal Plain (Figures 8, 9 and 10).
                                                       Thus, the Arctic rivers of this investigation have a generally later breakup than the
                                                       rivers of the previous two studies. This area where the river watersheds are restricted
                                                       to the Arctic Coastal Plain and the northern section of the Arctic Foothills
                                                       physiographic province is here designated the Barrow River Basin (Figure 11).
                                                                During the river breakup injune 1984, because of warm and relatively cloud
                                                       free weather, almost the entire snowpack in the Barrow River Basin melted within
                                                       two days (9 and 10june). As a result, the rivers of this study went from zero discharge
                                                       rates to almost bankfull channels in a matter of hours. Had the winter snowpack been
                                                       heavier than it was, the discharge rates would have been much higher than those
                                                       observed. It is apparent that the Arctic rivers of this investigation have the potential
                                                       of very high peak discharge rates during the spring breakup if the winter snowpack is
                                                       sufficiently heavy and melts rapidly.
                                                                After the winter snowpack has melted on the Arctic Coastal Plain the
                                                       discharge of the rivers in the Barrow River Basin quickly falls to a low level (Figure
                                                       12), and remains low throughout the summer unless additional precipitation is
                                                       received in the form of summJ rain.
                                                                The five Arctic rivers of the first North Slope Borough Floodplain Study
                                                       (Mortensen and Cannon, 1982) began spring breakup with water flowing over the
                                                       river channel ice and creating a large pond of pre-polynya water on the Arctic Ocean
                                                       ice at the mouth of the rivers. This water then drained off the ocean ice through
                                                       cracks and strudle holes, leaving a deposit of fine sand and silt behind. Of the eight
                                                       Arctic rivers of the second North Slope Borough Floodplain Study (Cannon, 1983)
                                                       only one river, the Pitmegea, exhibited this overice flow during the breakup of 1982.
                                                       The other seven rivers of Floodplain Study Number 2 began breakup by melting in
                                                       the mid-regions of their drainages, with water flowing under the ice in the lower
                                                       regions. The polynyas opened up by melting from the bottom of the ice up.
                                                                A significant difference between the rivers of this study and Floodplain
                                                       Studv Number 2 with the rivers of Studv Number I is the lack of aufeis. Aufeis causes
                                                       the temporary damming of a river, producing localized flooding. Though ice-block
                                                       damming was observed along the Meade River, no aufeis occurred along the rivers of
                                                       this investigation.
                                                                The spring breakup characteristics of each individual river of this investiga-
                                                       tion will be discussed later in the text, also see Figures 8 through 25.

                                                                                                                                               19

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                    Figure 8.
                    Landsat image 4068221080-7      (28  April 1984)  showing the spring    breakup flood waters
                    (black) of the Colville, Sagavanirktok and Shaviovik Rivers (of N.S.B. Floodplain Study No.
                    1) ponding on the near shore Arctic Ocean ice as pre-polynya water.     Notice that the @rctic
                    Coastal Plain in this image is still snow covered. The source of the     water in the rivers is
                    coming from the melting snowpack of the Brooks Range to the south. The scene is 185 km.
                    across (115 mi.). Compare to Figures 9, 10 and 13.

                    20

                                                                        N,

                                                                                -UTUKOK    R.

                                                          --- KASEGALUK LAGOON
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                                                      Figure 9.
                                                      Landsat image 5008821594-7 (28 April 1984) showing the breakup flood waters (black) of
                                                                                -
                                                                                     KOK   R-
                                                                                UTU

                                                          --- KASEGALUK LAGOON

                                                      theUtukok, Kokolikand Epizetka Rivers (of N.S.B. FloodplainStudy No. 2)pondingon,the
                                                      ice of Kasegaluk Lagoon as pre-polynya water. Notice that the Arctic Coastal Plain in this
                                                      image is still snow covered. The source of the water in the rivers is coming frorn the melting
                                                      snowpack of the Brooks Range to the southeast. The scene is 185 km. across (115 mi.).
                                                      Compare to Figures 8, 10 and 13.

                                                                                                                                               21

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                    Figure  10
                    Landsat image 5009221344-7        (01 June 1984) showing the lkpikpuk and Meade             River
                    channels (black) (of this investigation) nine days before breakup occurred on these rivers.
                    The silt and sand of the active river channels is moist, and there is some standing water in the
                    channels from local snowmelt. Notice that the prevailing winds have blown some of the silt
                    and sand onto the still snow covered Arctic Coastal Plain. There is no flowing water in the
                    river channels (four days after the images of Figures 8 and 9 were taken) because these river
                    drainages do not have their headwaters in the Brooks Range. The scene is 185 km. (115 mi.)
                    across. Compare to Figures 8, 9 and 13.

                    22

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                                                                                                                     Figure 11.
                                                                                                                     Map of the Barrow River Basin.

                                                                                                                                                                                                                                                                                                                     23

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                   Figure 12.
                   Landsat image 5010821350-7 (17june 1984) showing the lkpikpuk andMeade Rivers seven
                   davs after the start of breakup on 10june. The river channels still have flowing water, buttbe
                   discharge is much less than one week earlier. Notice that most of the talik lakes are still
                   frozen, but that the Arctic Coastal Plain is clear of snow. The scene is 185 km. across (115
                   mi.).

                   24

                                REAUFORT -SEA

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                                                      Figure 13.
                                                      Landsat image   5009320392-7    (02 June 1984) showing the rivers of the Arctic National
                                                      Wildlife Refuge and the Yukon Territory. This image was taken five days af ter the scenes of
                                                      Figures 8 and 9, and one day after the scene of Figure 10. The Arctic Coastal Plain is clear of
                                                      snow, the rivers have already undergone breakup, and the polynyas have started to open.
                                                      This scene is 185 km. across (115 mi.).

                                                                                                                                                25

                                                                                                                             M

                    Figure 14.
                    Very low altitude oblique aerial photograph taken from a Cessna 182 on 4 June 1984. This
                    view is looking upstream (south) along the main channel of the lkpikpuk River six days
                    before breakup occurred. Notice that the channel contains very little ice. The water in the
                    channel has come from local snowmelt. Compare to Figure 16.

                    26

                                                                                                                              231;

                                                                                                                                     IMP

                                                                                                                                       Y, "k-

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                                                      R",

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                                                     Figure 15.
                                                     Landsat image E-22306-21372-7 (16 May 1981) showing the dry sand (black) of the river
                                                     channels and the wind blown silt and sand (black) adjacent to the river charmcls. The only
                                                     river in this image that has abundant channel ice is the Meadc upstream (south) of the village
                                                     of Atkasook. The scctie is 185 km. (115 mi.) across,

                                                                                                                                             27

                                      +VO,45                           V050+                               V05s+                               V060+

                                                                 ..BEAUFORT SEA

                                                                                                   ITH
                                                                                    q  ot-     SM         (4
                                                                                               B
                                                                                                  Y
                                                                                                 A

                                                                                                                           TESHEKPUK
                                                                                                                           LAKE

                    Figure 16.
                    Landsat image E-30457-21401-7 (5 June 1979) showing the rivers at breakup. The water in
                    the channels is black in this image as is the pre-polynya water that is ponding on the ocean
                    ice of Dease Inlet and Smith Bay. Although the snow is gone from the Arctic Coastal Plain.
                    the talik lakes are still frozen. The scene is 18 5 km. (115 rni.) across.

                    28

                                                                                                                               4

                                                                             &A

                                                       3

                                                                                                                           '74

                                                      Figure 17.
                                                      An enlargement of Landsat image E-30457-?1401-7 (5june 1979) (of Figure    16) showing the
                                                      spring breakup flood waters (black) of the Meade River Delta (1) ponded on top of the ocean
                                                      ice of Admiralty Bay (2). Notice how the flood waters cover the interconnecting, and still
                                                      frozen, lakes on the delta. Oarlock Island is at 4. The scene is 35 km. (22 mi.) across.

                                                                                                                                               29

                                                                                          f
                                                                                          f
                                                                                          f

                                                                                                         F

                                                               ax,;?

                                                                                          wy,

                                                  NN,

                 Figure 18.
                 An enlargement of Landsat image E-30457-21401-7 (5 June 1979) (of Figure 16) showing the
                 spring breakup floodwaters (black) of the Ikpikpuk River ponded (])on topof theocean ice
                 of Smith Bay. The polynya has started to open at the boundary between the ocean ice and the
                 Ikpikpuk River Delta (2). The scene is 31 km. (20 mi.) across.

                 30

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                                                       Figure 19.
                                                       An enlargement of Landsat image E-30457-21401-7 (5 June 1979) (of Figure 16) showing the
                                                       spring breakup flood waters (black) (1) of the Topagoruk River (2) ponded on top of the
                                                       ocean ice of Admiralty Bay. As the depth of the ponded water increases it may flood adjacent
                                                       low lying areas of the coastal plain (3). The scene is 29 km. (18 mi.) across.

                                                                                                                                                  31

                                                                                                                                       r
                                                            N
                                                                                                                                        4j
                                  7@                                                                                             w
                                                                                                                           in-4,

                                                                                                                                       42

                  Figure 20.
                  A low altitude oblique aerial photograph taken froma Cessna 182 on 10june 1984 looking
                  northeast across the southern end of Admiralty Bay and the delta of the Topagoruk River.
                  The breakup waters of the Topagoruk River are just reaching the delta. The pre-polynya
                  water will begin to pond on the ocean ice in the next few days, flooding low lying areas
                  adjacent to the shore. Compare to Figure 19.

                  32

                                                                                   BEAUFORT SEA
                                         Al

                                                                                                      S M I T'H@
                                                                                                      BAY

                                     --BARROW

                                                                                      E   I NLE

                                                      Figure 21.
                                                      Landsat image E-2902-21175-5 (12 July 1977) showing the rivers after breakup. Notice the
                                                      plumes of sediment (lighter areas in thdark ocean water) in Dease Inlet and Smith Bav. The
                                                      rivers now have a very low discharge and the river channels are almost dry (xvhite areas
                                                      along the rivers). The scene is 185 kni. (115 mi.) across. Compare to Figures 22 and 23.

                                                                                                                                              33

                 Figure 22.
                 An enlargement of Landsat image E-2902-21175-5 (12july 1977) (of Figure 21) showing the
                 sediment plumes in the ocean water of the open polynya at the mouth of the Ikpikpuk River.
                 The scene is 34 km. (21 mi.) across. Compare to Figure 21.

                 34

                                                                                                   ALI

                                                      Figure 23.
                                                      Anenlargement of Landsat image E-2902-21175-5 (12july 1977)(of Figure 21)showing the
                                                      lkpikpuk, Chipp and Ournalik Rivers at very low discharge. The white areas in this scene are
                                                      the dryactive channels of the rivers. This scene is 34 km. (21 mi.) across. Compare to Figure
                                                      21.

                                                                                                                                                35

                  Figure 24.
                  Landsat irnage E-30423-21520-7 (2 May 1979) showing the Kuk River and its tributaries
                  before breakup. Notice that the lower regions of the Kuk and Ivisarnk Rivers are covered by
                  channel ice. At breakup the waters of the Kuk and Ivisaruk Rivers will pond on top of the ice
                  of the Kuk River Estuarv similar to pre-polvriva water on ocean ice (compare to Figure 25).
                  The scene is 185 km. (1'15 mi.) across.

                  36

                                         WAINWRIGHT---

                         r                                                        --KUK R. ESTU
                                                                                                                                      A

                                                                                                                   V4           W
                                                                                                           V
                                                                                                           5
                                                                                                                          -A"
                                                                                                                                  S

                                                                                                                  4
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                                                                                                                     U

                                                  Figure 25.
                                                  An enlargement of Landsat image   E-2508-21450-5 (13 June 1976) showing the breakup
                                                  flood waters (black) of the Kuk and Ivisaruk Rivers flowing across and ponding on top of the
                                                  ice of the Kuk River Estuary. The scene is 102 km. (63 mi.) across.

                                                                                                                                     37

                                                      Floodplain Geoinorphology and Flooding Potential
                                                      of the Study Rivers

                                                      lkpikpuk River

                                                               The lkpikpuk River is located on the Teshekpuk and lkpikpuk River
                                                      1:250,000 USGS quadrangle maps. The flooding units of the lkpikpuk River are
                                                      shown on Maps la, lb, Ic and Id. A total of 268.3 miles of the lkpikpuk River active
                                                      channel was mapped from Smith Bay to the Maybe Creek/Kigalik River junction,
                                                      including the distributary channels (Appendix A). The lkpikpuk River has the largest
                                                      watershed area (Table 3) of the rivers studied in this investigation. It is a meandering
                                                      stream that is slightly incised to slightly entrenched in the upper part of its drainage.
                                                      It has a gradient of 1.2 feet per mile (Table 2, Appendix C, Figures 49 and 50).
                                                               Spring breakup starts with water flowing over an essentially dry channel that
                                                      has only small amounts of ice in it. Localized flooding caused by ice jams is a minor to
                                                      moderate flooding hazard on the lkpikpuk River.
                                                               Childers (1979) has estimated that the Ikpikpuk River has a bankfull channel
                                                      discharge of 1,274 m3/sec. (45,000 ft.3/sec.) and a 50 year flood discharge of 2,095
                                                      M3/sec. (74,000 ft.3/sec.) The mean annual precipitation of the river basin is 23 cm.
                                                      (9 in.).

                                                               Map Flood Units, lkpikpuk River
                                                               I = low magnitude - high frequency flooding:
                                                      Physiographically the lowest active floodplain which is covered by water every year.
                                                      This unit is the active channel which exhibits annual change and is bare of
                                                      vegetation.
                                                               2 = intermediate magnitude - intermediate frequency flooding:
                                                      There is not a sharp physiographic break between flood units I and 2. Flood unit 2 is
                                                      mainly covered with grasses with sparse groves of low willows. This unit shows the
                                                      effects of recent erosion and deposition by running water. The estimated flooding
                                                      frequency is 3 to 10 years.
                                                               3 = high magnitude - low frequency flooding:
                                                      This unit is physiographically higher than flood unit 2. There is a gradational to
                                                      definite physiographic break between units 2 and 3. Unit 3 shows the scars of
                                                      running water but has a good cover of tundra and some grasses. Vegetated eolian sand
                                                      dunes may be common in places. It has minor permanent ice features such as
                                                      polygons and patterned ground. The estimated flooding frequency is 10 to 50 years.
                                                               4 = rarely floods, very high magnitude - very low frequency flooding:
                                                      This flooding unit is physiographically the highest active floodplain. There is a
                                                      definite physiographic break between this flood unit and flood unit 3. This unit has a
                                                      well established cover of tundra. Flood unit 4 shows the old scars of running water.
                                                      This unit strongly exhibits the features of an ice-rich, permanently frozen material.
                                                      Such features as patterned ground, high and low centered polygons, and poor
                                                      drainage characterize this unit. Contains vegetated eolian sand dunes. Areas of flood
                                                      unit 4 on Map I a may not flood. The estimated flooding frequency is 100 to 200
                                                      years.
                                                               5 = no flooding:
                                                      There is no physiographic break between flood units 5 and 4. Flood unit 5 is probably

                                                                                                                                             39

                    at the limit of the Project Flood. It has the same geornorphology as unit 4.
                              6 = high floodplain terrace or eolian dune on the floodplain, no flooding:
                    This unit is physiographically higher than flooding units 4 and 5 and there is a
                    definite physiographic break between non-flood unit 6 and units 4 and 5.
                              7 =* very high floodplain terrace, no flooding:
                    This unit is phN,siographically higher than non-flood unit 6 and there is a definite
                    physiographic break between units 6 and 7.

                                Table 7. General Geomorphic River Channel Characteristics

                    River
                    (This Investigation)
                    lkpikpuk                     Meandering,   Slightly Incised. Slight Entrenchment
                    Chipp                        Meandering
                    Alaktak                      Meandering
                    Miguakiak                    Meandering, Yazoo Stream
                    PiaSUk                       Meandering,   Underfit Stream
                    Odinalik                     Meandering, Slightly Incised
                    Topagoruk                    Meandering,   Slightly Incised
                    Meade                        Incised Meandering, Slight Entrenchment to Entrenched
                    USUktUk                      Meandering, Slightly Incised
                    Ivisaruk                     Incised Meandering, Slight Entrenchment
                    KUk                          Estuarine, Slightly Meandering, Slight Entrenchment
                    Kaotak                       Incised Meandering, Slight Entrenchment
                    Ketik                        Incised Meandering, Slight Entrenchment
                    Avalik                       Incised Meandering, Slight Entrenchment
                    Ongorakvik                   Straight to Slightly Meandering, Incised
                    Nokotlek                     Straight to Slightly Meandering, Incised
                    Kugrua                       Meandering
                    Tunalik                      Straight to Slightly Meandering, Incised, Slight Entrenchment

                    (Cannon.1983)

                    Avak                         Incised Meandering
                    Utukok                       Incised Meandering, Slightly Braided
                    Kokolik                      Incised Meandering
                    Epizetka                     Incised Meandering, Slight Entrenchment
                    Kukpowruk                    Incised Meandering, Slight Entrenchment
                    Pitmegea                     Braided
                    lpewik                       Entrenched Meandering
                    KUkpUk                       Entrenched Meandering

                    (Mortensen and Cannon, 1982)

                    Colville                   - Braided-Meandering, Slight Entrenchment
                    Kuparuk                      Meandering, Slightly Braided
                    Sagavanirktok                Braided- Meandering, Underfit Stream
                    Shaviovik                    Braided-Meandering
                    Canning                      Braided

                    Note: An entrenched stream is one in which the stream is cut down into bedrock. An
                              incised stream differs from this bv not being related to tectonic uplift, and refers to
                              the floodplains being set into the'surrounding alluvial materials.

                    40

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                                                   @ �r

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                                                       Figure 26.
                                                       A NASA high altitude infrared aerial photograph of the lkpikpuk River Delta (the black areas
                                                       are water) which is an actively prograding (growing) delta. Compare this photograph to
                                                       Figure 6 of the Meade River Delta. The scene is 15 km. (9 mi.) across. Roll number 2790,
                                                       frame number 3138, July 19" 9.

                                                                                                                                                  41

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                                                                                      A

                                                                                                         '4
                                                                                                           0

                   Figure 27.
                   A very low altitude aerial photograph taken from a Bell 206 helicopter on 3 August 1984.
                   This view is looking north across a part of the lkpikpuk River Delta. The log in the
                   foreground is approximately 50 feet long and was deposited on this tundra covered part of
                   the delta bv an ocean storm surge. An ocean storm surge may cause widespread flooding
                   across the lkpikpuk River Delta area.

                   42

                                                                       4,
                                 A; INk,
                                                                                        4'@pl

                                                      Figure 28.
                                                      Aphotograph taken from the groundon 3 August 1984 showing an "abandoned" channel of
                                                      the lkpikpuk River. This channel is a flood unit 3, while the high ground on the left of the
                                                      channel is a non-flood unit 5.

                                                                                                                                            43

                                                    Chipp River

                                                             The Chipp River is located on the Teshekpuk 1:250,000 USGS quadrangle
                                                    inap. The flooding units of the Chipp River are shown on Maps la and 1b. A total of
                                                    62.0 miles of the Chipp, River active channel was mapped from Admiralty Bay to the
                                                    junction with the Ikpikpuk River (Appendix A). The Chipp, River is both a
                                                    distributary channel of the lkpikpuk River and an extension of the Oumalik River.
                                                    Because of this the exact area of its watershed cannot be calculated. The Chipp/
                                                    OUnialik watershed is 1,485 square miles (Table 3). The Chipp River is a meandering
                                                    stream. It has a gradient of 0.9 feet per mile (Table 2, Appendix C, Figures 49 and 50).
                                                             Spring breakup starts with water flowing over an essentially dry channel that
                                                    has only small amounts of ice in it (Figure 29). Localized flooding caused by ice jams
                                                    is a minor to moderate flooding hazard on the Chipp River. However, talik lake
                                                    breaching is a major flooding hazard on the Chipp River (see Figures 30 to 34).

                                                             Map Flood Units, Chipp River
                                                             I = low magnitude - high frequency flooding:
                                                    Physiographically the lowest active floodplain which is covered by water every year.
                                                    This unit is the active channel which exhibits annual change and is bare of
                                                    vegetation.
                                                             2 = intermediate magnitude - intermediate frequency flooding:
                                                    There is not a sharp phvsiographic break between flood units I and 2. Flood unit 2 is
                                                    mainly covered with grasses with sparse groves of low willows. This unit shows the
                                                    effects of recent erosion and deposition by running water. The estimated flooding
                                                    freqLiencv is 3 to 10 years.
                                                             3 = high magnitude - low frequency flooding:
                                                    This unit  is physiographically higher than flood unit 2. There is a gradational to
                                                    definite phvsiographic break between units 2 and 3. Unit 3 shows the scars of
                                                    running water but has a good cover of tundra and some grasses. Vegetated eolian sand
                                                    dunes may be common in places. It has minor permanent ice features such as
                                                    polygons and patterned ground. The estimated flooding frequency is 10 to 50 years.
                                                             4 = rarely floods, very high magnitude - very low frequency flooding:
                                                    This flooding unit is physiographically the highest active floodplain. There is a
                                                    definite physiographic break between this flood unit and flood unit 3. This unit has a
                                                    well established cover of tundra. Flood unit 4 shows the old scars of running water.
                                                    This unit strongly exhibits the features of an ice-rich, permanently frozen material.
                                                    Such features as patterned ground, high and low centered polygons, and poor
                                                    drainage characterize this unit. Contains vegetated eolian sand dunes. Areas of flood
                                                    unit 4 on Map I a may not flood. The estimated flooding frequency is 100 to 200
                                                    years.
                                                             5 = no flooding:
                                                    There is no physiographic break between flood units 5 and 4. Flood unit 5 is probably
                                                    at the limit of the Project Flood. It has the same geomorphology as unit 4.
                                                             6 = high floodplain terrace or eolian dune on the floodplain, no flooding:
                                                    This unit is physiographically higher than flooding units 4 and 5 and there is a
                                                    definite physiographic break between non-flood unit 6 and units 4 and 5.

                                                                                                                                          45

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                  Figure 29.
                  A low altitude oblique aerial photograph taken from a Cessna 182 on 10june 1984. The view
                  is looking north (downstream) along the Chipp River during the rising stage of the spring
                  breakup flood waters. Notice the small amount of block ice floating in the channel. The
                  localized flooding produced by ice jams in the channel is probably only a minor to moderate
                  flooding hazard on the lkpikpuk, Alaktak, Chipp and Topagoruk Rivers.

                  46

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                                                           Figure 30.
                                                           A NASA high altitude infrared aerial photograph of the Chipp and Alaktak Rivers. The black
                                                           areas are water, the white areas are dry sand of the active river channels (north is at the top).
                                                           This scene shows where the Chipp River has breached a series of four talik lakes (2, 3, 4 and
                                                           5) adjacent to the former main channel (1) of the Chipp River. The river has breached the
                                                           lakes, drained them and then formed a new channel through the drained lakes within the
                                                           last 3 5 years (the river is flowing to the upper left). This process of lake breaching along the
                                                           Chipp River would be a major hazard to permanent facilities built adjacent to the river. The
                                                           Chipp River may be changing its course in this manner because of 1) localized subsidence
                                                           due to the loss of ground ice, or 2) as a response to regional tectonic subsidence. Also see
                                                           Figures 31 to 34. The scene is 15 km. (9 mi.) across. Roll number 23, frame number 35, July
                                                           1977.

                                                                                                                                                         47

                                               R.

                                                                                                 -W

                 Figure 31.
                 A black and white aerial photograph of the Chipp and Alaktak Rivers taken in August 1955
                 showing the series of talik lakes that will later be breached by the Chipp River to form a new
                 channel. The lake numbers correspond to the numbers of Figures 30 and 32. Notice how
                 lake number 2 has already been breached by the Chipp River. Also see Figures 33 and 34. The
                 scene is 9 km. (5.6 mi.) across. USGS aerial photography, Mission 57, Roll 106, frame number
                 13734, 13 August 1955.

                 48

                                                                                                                              P R.

                                                         7

                                                      Figure 32.
                                                      A low altitude oblique aerial photograph taken frorn a Cessna 182 on 10june 1984. The view
                                                      is looking east across breached talik lake No. 2 (see Figures 30 and 31). During spring
                                                      breakup the majority of the Chipp River's discharge is flowing through this new channel.

                                                                                                                                              49

                                                                        100

                  Figure 33.
                  An enlargement of Landsat image E-30457-214()1-7 (5june 1979) (of Figure 16) showing the
                  spring breakup flood water (black) of the Chipp River filling Lip and flowing through the
                  breached talik takes of Figures 30, 31, and 32. Compare this image to Figure 34 which was
                  taken after the spring breakup water had receded. The scene is 56 km. (35 rni.) across.

                  50

                                                                 'PP R.

                                                                           1P

                                                     Figure 34.
                                                     An enlargement of Landsat image E-2902-21175-5 (12july 191, 7) (of Figure 21) showing the
                                                     active channels (white areas)of the Chipp and Alaktak Rivers afterthe springbreakup flood
                                                     waters have receded. Notice the breached lakes and compare to Figure 33. The scene is 58
                                                     @Im- (36 mi.) across.

                                                                                                                                             51

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                                                                                                                                          I EVIR,

                                                                                                        LOCATI

                   Figure 35.
                   A NASA high altitude infrared aerial photograph of the Chipp River Delta area (the black
                   areas are water). Notice that where the Chipp River empties into Admiralty Bay that there is
                   no true delta. Talik lake breaching (Figures 30 to 34) appears to be a common process along
                   the Chipp River floodplain. The features at " I " are all breached talik lakes that have now
                   been partly filled with river transported sediments. The feature in the box is a breached talik
                   lake along the main channel of the Chipp River that is presently being filled by river
                   sediments (see Figure 36). The scene is 15 km. (9 mi.) across. Roll number 2790, frame
                   number 3145, July 1979.

                   52

                                                                        P                              PITTALUKRUAK LAKE

                                                 P@

                                                                                                   --- BREACHED LAKE

                                                                                                                              9:0 M@"

                                                                                                                  J
                                                                                                                    V

                                                                                              V

                                                       Figure 36.
                                                       A low altitude black and  white  aerial photograph taken by the U.S. Navy    in 1949. This
                                                       photograph is aclose-upof thebreached taliklakeof Figure 35. Compare these two figures
                                                       to see changes from the two photographs taken 30 years apart. The scene is 4.3 km. (2.7 mi.)
                                                       across. U.S. Navy (BAR), Roll number 23, frame number 32. 1949.

                                                                                                                                                53

                                                    Alaktak River

                                                             The Alaktak River is located on the Teshekpuk 1:250,000 USGS quadrangle
                                                    map. The flooding units of the Alaktak River are shown on Map Ia. A total of 4 3.5
                                                    miles of the Alaktak River active channel was mapped from Pittalukruak Lake to the
                                                    junction with the lkpikpuk River (Appendix A). The Alaktak River is a distributary
                                                    channel of the lkpikpuk River; because of this its watershed cannot be calculated. It is
                                                    a meandering stream. It has a gradient of 0.6 feet per mile (Table 2, Appendix C,
                                                    Figures 49 and 50).
                                                             Spring breakup starts with water flowing over an essentially dry channel that
                                                    has only small amounts of ice in it. Localized flooding caused by ice jams is a minor to
                                                    moderate flooding hazard on the Alaktak River.

                                                             Map Flood Units, Alaktak River
                                                             I = low magnitude - high frequency flooding:
                                                    Physi ographically the lowest active floodplain which is covered by water every year.
                                                    This unit is the' active channel which exhibits annual change and is bare of
                                                    vegetation.
                                                             2 = intermediate magnitude - intermediate frequency flooding:
                                                    There is not a sharp physiographic break between flood units I and 2. Flood unit 2 is
                                                    mainly covered with grasses with sparse groves of low willows. This unit shows the
                                                    effects of recent erosion and deposition by running water. The estimated flooding
                                                    frequencv is 3 to 10 years.
                                                             3 = high magnitude - low frequency flooding:
                                                    This unit is physiographically higher than flood unit 2. There is a gradational to
                                                    definite physiographic break between units 2 and 3. Unit 3 shows the scars of
                                                    running water but has a good cover of tundra and some grasses. Vegetated eolian sand
                                                    dunes may be common in places. It has minor permanent ice features such as
                                                    polygons and patterned ground. The estimated flooding frequency is 10 to 50 years.
                                                             4 = rarely floods, very high magnitude - very low frequency flooding:
                                                    This flooding unit is physiographically the highest active floodplain. There is a
                                                    definite physiographic break between this flood unit and flood unit 3. This unit has a
                                                    well established cover of tundra. Flood unit 4 shows the. old scars of running water.
                                                    This unit strongly exhibits the features of an ice-rich, permanently frozen material.
                                                    Such features as patterned ground, high and low centered polygons, and poor
                                                    drainage characterize this unit. Contains vegetated eolian sand dunes. Areas of flood
                                                    unit 4 on Map Ia may not flood. The estimated flooding frequency is 100 to 200
                                                    years.
                                                             5 = no flooding:
                                                    There is no physiographic break between flood units 5 and 4. Flood unit 5 is probably
                                                    at the limit of the Project Flood. It has the same geomorphology as unit 4.
                                                             6 = high floodplain terrace or eolian dune on the floodplain, no flooding:
                                                    This unit is physiographically higher than flooding units 4 and 5 and there is a
                                                    definite physiographic break between non-flood unit 6 and units 4 and 5.

                                                                                                                                           55

                                                       Miguakiak River

                                                                The Miguakiak River is located on the Teshekpuk 1:250,000 USGS quadran-
                                                       gle map. The flooding units of the Miguakiak River are shown on Map Ia. A total of
                                                       20.3 miles of the Miguakiak River active channel was mapped from Teshekpuk Lake
                                                       to the junction with the Ikpikpuk River (Appendix A). It is a meandering, Yazoo type
                                                       stream (Figure 37).
                                                                The Miguakiak River flows from Teshekpuk Lake to the lkpikpuk River.
                                                       Spring breakup starts with the flood waters of the Ikpikpuk River flowing backward
                                                       up the still frozen and ice covered channel of the Miguakiak River. Because of this, the
                                                       Miguakiak is a Yazoo type stream, and has the same flooding potential as the Ikpikpuk
                                                       River.

                                                                Map Flood Units, Miguakiak River
                                                                I = low magnitude - high frequency flooding:
                                                       Physiographically the lowest active floodplain which is covered by water every year.
                                                       This unit is the active channel which exhibits annual change and is bare of
                                                       vegetation.
                                                                2 = intermediate magnitude - intermediate frequency flooding:
                                                       There is not a sharp physiographic break between flood units I and 2. Flood unit 2 is
                                                       mainly covered with grasses with sparse groves of low willows. This unit shows the
                                                       effects of recent erosion and deposition by running water. The estimated flooding
                                                       frequency is 3 to 10 years.
                                                                3 = high magnitude - low frequency flooding:
                                                       This unit is physiographically higher than hood unit 2. There is a gradational to
                                                       definite physiographic break between units 2 and 3. Unit 3 shows the scars of
                                                       running water but has a good cover of tundra and some grasses. Vegetated eolian sand
                                                       dunes may be common in places. It has minor permanent ice features such as
                                                       polygons and patterned ground. The estimated flooding frequency is 10 to 50 years.
                                                                4 = rarely floods, very high magnitude - very low frequency flooding:
                                                       This flooding unit is physiographically the highest active floodplain. There is a
                                                       definite physiographic break between this flood unit and flood unit 3. This unit has a
                                                       well established cover of tundra. Flood unit 4 shows the old scars of running water.
                                                       This unit strongly exhibits the features of an ice-rich, permanently frozen material.
                                                       Such features as patterned ground, high and low centered pol            ygons, and poor
                                                       drainage characterize this unit. Contains vegetated eolian sand dunes. Areas of flood
                                                       unit 4 on Map Ia may not flood. The estimated flooding frequency is 100 to 200
                                                       years.   5 = no flooding:
                                                       There is no physiographic break between flood units 5 and 4. Flood unit 5 is probably
                                                       at the limit of the Project Flood. It has the same geornorphology as unit 4.

                                                                                                                                               57

                                                                                                              VA"
                                                 52

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                                                  .AI

                  Figure 37.
                  A low altitude oblique aerial photograph taken from a Cessna 182 on 10 June 1984. This
                  view is looking east (upstream) along the Miguakiak River at spring breakup showing the
                          7

                  dark sediment laden water from the lkpikpuk River flowing backward up the still frozen
                  channel of the Miguakiak River. The Miguakiak River normally drains water from Teshekpuk
                  Lake (see Map I a) to the lkpikpuk River. However, during the spring breakup, the flood
                  waters from the Ikpikpuk River flow backward up the Miguakiak River. The Miguakiak River
                  is a Yazoo type stream.

                  58

                                                     Piasuk River

                                                              The Piasuk River is located on the Teshekpuk 1:250,000 USGS quadrangle
                                                     map. The flooding units of the Piasuk River are shown on Map Ia. A total of 13.0 miles
                                                     of flood unit I was mapped from Smith Bay (Appendix A). The Piasuk River has no
                                                     true watershed area as it is an "abandoned" distributary channel of the lkpikpuk
                                                     River. It is an underfit meandering stream (Table 7). Its gradient is too low and
                                                     channel too short to calculate the gradient from USGS topographic maps.
                                                              The Piasuk River is connected to the lkpikpuk River distributary system by
                                                     .'abandoned" channels, that are designated as flood unit 3. Thus, it receives water
                                                     from the lkpikpuk River only when a stage 3 flood occurs on that river. (See Figure 28
                                                     for an example of a flood unit 3 channel.)

                                                              Map Flood Units, Piasuk River
                                                              I = the former active channel:
                                                     It is at present no more than a long lake that receives water from local snowmelt
                                                     during the spring breakup.
                                                              2 = there is no flood unit 2 on the Pia'suk River.
                                                              3 = high magnitude - low frequency flooding:
                                                     This unit is physiographically higher than flood unit 1. The areas of this flood unit are
                                                     vegetated "abandoned" channels of the Ikpikpuk River distributary system. The
                                                     estimated flood frequency is the same as the lkpikpuk River - 10 to 50 years.
                                                              4 = rarely floods, very high magnitude - very low frequency flooding:
                                                     This flooding unit is physiographically the highest active floodplain. There is a
                                                     definite physiographic break between this flood unit and flood unit 1. This unit has a
                                                     well established cover of tundra. Flood unit 4 shows the old scars of running water.
                                                     This unit strongly exhibits the features of an ice-rich, permanently frozen material.
                                                     Such features as patterned ground, high and low centered polygons, and very poor
                                                     drainage characterize this unit. Areas of flood unit 4 on Map Ia may not flood. The
                                                     estimated flooding frequency is 100 to 200 years.
                                                              5 = no flooding:
                                                     There is no physiographic break between flood units 5 and 4. Flood unit 5 is probably
                                                     at the limit of the Project Flood. It has the same geomorphology as unit 4.
                                                              I'd = fluvial delta deposits of the now mostly inactive Piasuk River Delta:
                                                     This area is subject to ocean storm surge flooding.

                                                                                                                                            59

                                                      Oumalik River

                                                                The Ournalik River is located on the Teshekpuk, lkpikpuk River and
                                                      Lookout Ridge 1:250,000 USGS quadrangle maps. The flooding units of the Ournalik
                                                      River are shown on Map lb. A total of 40.0 miles of the Oumalik River active channel
                                                      was mapped from the junction with the Chipp River to the 75 foot topographic
                                                      contour (Appendix A). The Ournalik River has a watershed area of 1,475 square miles
                                                      (Table 3). It is a meandering to slightly incised stream (Table 7). It has a gradient of 0. 5
                                                      feet per mile (Table 2, Appendix C, Figure 49).
                                                                Spring breakup starts with water flowing over an essentially dry channel that
                                                      has only small amounts of ice in it. Localized flooding caused by ice jams is a minor to
                                                      moderate flooding hazard on the Oumalik River.

                                                                Map Flood Units, Oumalik River
                                                                I = low magnitude - high frequency flooding:
                                                      Physiographically the lowest active floodplain which is covered by water every year.
                                                      This unit is the active channel which exhibits annual change and is bare of
                                                      vegetation.
                                                                2 = intermediate magnitude - intermediate frequency flooding:
                                                      There is not a sharp physiographic break between flood units I and 2. Flood unit 2 is
                                                      mainly covered with grasses with sparse groves of low willows. This unit shows the
                                                      effects of recent erosion and deposition by running water. The estimated flooding
                                                      frequency is 3 to 10 years.
                                                                @ = high magnitude - low frequency flooding:
                                                      This unit is physiographically higher than flood unit 2. There is a gradational to
                                                      defin ite physiographic break between units 2 and 3. Unit 3 shows the scars of
                                                      running water but has a good cover of tundra and some grasses. Vegetated colian sand
                                                      dunes may be common in places. It has minor permanent ice features such as
                                                      polygons and patterned ground. The estimated flooding frequency is 10 to 50 years.
                                                                4 = rarely floods, very high magnitude - very low frequency flooding:
                                                      This flooding unit is physiographically the highest active floodplain. There is a
                                                      definite physiographic break between this flood unit and flood unit 3. This unit has a
                                                      well established cover of tundra. Flood unit 4 shows the old scars of running water.
                                                      This unit strongly exhibits the features of an ice-rich, permanently frozen material.
                                                      Such features as patterned ground, high and low centered polygons, and poor
                                                      drainage characterize this unit. Contains vegetated eolian sand dunes. Areas of flood
                                                      unit 4 on Map la may not flood. The estimated flooding frequency is 100 to 200
                                                      years.
                                                                5 = no flooding:
                                                      There is no physiographic break between flood units 5 and 4. Flood unit 5 is probably
                                                      at the limit of the Project Flood. It has the same geomorphology as unit 4.
                                                                6 = high floodplain terrace or eolian dune on the floodplain, no flooding:
                                                      This unit is physiographically higher than flooding units 4 and 5 and there is a
                                                      definite physiographic break @etween non-flood unit 6 and units 4 and 5.

                                                                                                                                                 61

                                                      Topagoruk lUver

                                                               The Topag0ruk River is located on the Teshekpuk, Meade River and Lookout
                                                      Ridge 1:250,000 USGS quadrangle maps. The flooding units of the Topagoruk River
                                                      are shown on Maps la and lb. A total of 115.5 miles of the Topagoruk River active
                                                      channel was mapped from Admiralty Bay to the 100 foot topographic contour
                                                      (AppendixA). The Topagoruk River has a watershed area of 783.0 squaremiles (Table
                                                      3). It is a meandering stream that is slightly incised in the upper part of its drainage
                                                      (Table 7). It has a gradient of 1.0 foot per mile (Table 2, Appendix C, Figure 49).
                                                               Spring breakup starts with water flowing over an essentially dry channel that
                                                      has only small amounts of ice in it. Localized flooding caused by ice jams is a minor to
                                                      moderate flooding hazard on the Topagoruk River.

                                                               Map Flood Units, Topagoruk River
                                                               1 = low magnitude - high frequency flooding:
                                                      Physiographically the lowest active floodplain which is covered by water every year.
                                                      This unit is the active channel which exhibits annual change and is bare of
                                                      vegetation.
                                                               2 = intermediate magnitude - intermediate frequency flooding:
                                                      There is not a sharp physiographic break between flood units I and 2. Flood unit 2 is
                                                      mainly covered with grasses with sparse groves of low willows. This unit shows the
                                                      effects of recent erosion and deposition by running water. The estimated flooding
                                                      frequency is 3 to 10 years.
                                                               3 = high magnitude - low frequency flooding:
                                                      This unit is physiographically higher than flood unit 2. There is a gradational to
                                                      definite physiographic break between units 2 and 3. Unit 3 shows the scars of
                                                      running water but has a good cover of tundra and some grasses. Vegetated eolian sand
                                                      dunes may be common in places. It has minor permanent ice features such as
                                                      polygons and patterned ground. The estimated flooding frequency is 10 to 50 years.
                                                               4 @ rarely floods, very high magnitude - very low frequency flooding:
                                                      This flooding unit is physiographically the highest active floodplain. There is a
                                                      definite physiographic break between this flood unit and flood unit 3. This unit has a
                                                      well established cover of tundra. Flood unit 4 shows the old scars of running water.
                                                      This unit strongly exhibits the features of an ice-rich, permanently frozen material.
                                                      Such features as patterned ground, high and low centered polygons, and poor
                                                      drainage characterize this unit. Contains vegetated eolian sand dunes. Areas of flood
                                                      unit 4 on Map la may not flood. The estimated flooding frequency is 100 to 200.
                                                      years.
                                                               5 = no flooding:
                                                      There is no physiographic break between flood units 5 and 4. Flood unit 5 is probably
                                                      at the limit of the Project Flood. It has the same geomorphology as unit 4.
                                                               6 = high floodplain terrace or eolian dune on the floodplain, no flooding:
                                                      This unit is physiographically higher than flooding units 4 and 5 and there is a
                                                      definite physiographic break between non-flood unit 6 and units 4 and 5.

                                                                                                                                            63

                                                                     @4-

                                                                                                           OT

                                                         V

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                                                                                                                     RUK R.

                Figure 38.
                A NASA high altitude infrared aerial photograph of part of the Meade River Delta and the
                Topagoruk River Delta (the black areas are water). The Topagoruk River has a small delta in
                comparison to the size of its drainage basin. Compare to Figures 19 and 20. The scene is 15
                km. (9 mi.) across. Roll number 2790, frame number 3147, July 1979.

                64

                                                       Meade River

                                                                The Meade River is located on the Meade River and Lookout Ridge
                                                       1:250,000 USGS quadrangle maps. The flooding units of the Meade River are shown
                                                       on Maps 2a, 2b and 2c. A total of 212.4 miles of the Meade River active channel was
                                                       mapped from Admiralty Bay to the 200 foot topographic contour, including the
                                                       distributary channels (Appendix A). The Meade River has the third largest watershed
                                                       area, 3,885.0 square miles (Table 3), of the rivers studied in this investigation. It is a
                                                       meandering river that is incised to slightly entrenched and entrenched in the upper
                                                       part of its drainage (Table 7). It has a gradient of 1. 3 feet per mile (Table 2, Appendix C,
                                                       Figure 49).
                                                                Spring breakup starts with water flowing over the channel ice. Localized
                                                       flooding caused by ice jams is a major flooding hazard on the Meade River (Figures
                                                       39, 40 and 41).
                                                                Childers (1979) has estimated that the Meade River has a bankfull channel
                                                       discharge, adjacent to thevillage of Atkasook, of 246 M3/sec. (8,700 ft.3/sec.) anda 50
                                                       year flood discharge of 1,076 M3/sec. (38,000 ft. 3/sec.). The mean annual precipita-
                                                       tion of the river basin is 20 cm (8 in.).

                                                                Map Flood Units, Meade River
                                                                I = low magnitude - high frequency flooding:
                                                       Physiographically the lowest active floodplain unit which is covered by water every
                                                       year. This unit is the active channel which exhibits annual change and is bare of
                                                       vegetation.
                                                                2 = intermediate magnitude - intermediate frequency flooding:
                                                       There is not a sharp physiographic break between flood units I and 2. Flood unit 2 is
                                                       mainly covered with grasses with some groves of low willows. This unit shows the
                                                       effects of recent erosion and deposition by running water. Eolian sand dunes may be
                                                       common in places. The estimated flooding frequency is 3 to 7 years.
                                                                3 = high magnitude - low frequency flooding:
                                                       This unit is physiographically higher than flood unit 2. There is a gradational to
                                                       definite physiographic break between units 2 and 3. Unit 3 shows the scars of
                                                       running water but has a good cover of tundra and some grasses. Vegetated eolian sand
                                                       dunes may be common in places. It has minor permanent ice features such as
                                                       polygons and patterned ground. The estimated flooding frequency is 7 to 25 years.
                                                                4 = rarely floods, very high magnitude - very low frequency flooding:
                                                       This flooding unit is physiographically the highest active floodplain. There is a
                                                       definite physiographic break between this flood unit and unit 3. This unit has a well
                                                       established cover of tundra. Flood unit 4 shows the old scars of running water. This
                                                       unit strongly exhibits the features of an ice-rich, permanently frozen material. Such
                                                       features as patterned ground, high and low centered polygons, and poor drainage
                                                       characterize this unit. Contains vegetated eolian sand dunes. The estimated flooding
                                                       frequency is 50 to 100 years.
                                                                5 = no flooding:
                                                       There is no physiographic break between flood units 5 and 4. Flood unit 5 is probably
                                                       at the limit of the Project Flood. It has the same geomorphology as unit 4.
                                                                6 = high floodplain terrace -or eolian dune on the floodplain, no flooding..
                                                       This unit is physiographically higher than flooding units 4 and 5 and there is a
                                                       definite physiographic break between non-flood unit 6 and units 4 and 5.

                                                                                                                                                 65

                                                                                       AIMIZ'R
                                                             "M

                                                           AA

                                                            -Ph L

                                                                                                          IN.

                   Figure 39.
                   A low altitude oblique aerial photograph taken frorn a Cessna 182 on      10 June 1984. This
                   view is looking downstream (north) along the Meade River at spring breakup. The village of
                   Atkasook is at the upper left. In this photograph the channel ice is being floated up from the
                   river channel bottom by the rising spring breakup flood waters. The source of the channel
                   ice is the deeper pools of water that are in the river at freezeup in the fall, when the river
                   commonly has a very low or zero discharge. The channel ice, 1) decreases the water flow
                   capacity of the river channel during spring breakup, 2) is the source of the ice blocks that
                   form ice jams on the river, 3) large pans of channel ice can block the river channel causing
                   the smaller floating ice blocks to forman ice jam. Ice jams are a major flooding hazard along
                   the Meade River during spring breakup.

                   66

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                                    WN't"
                                          hD.
                                                       V
                                                                             p
                                                                                                  V-@   V".

                                                                _A,

                                                      Figure 40.
                                                      A low altitude oblique aerial photograph taken from a Cessna    182 on 10 June 1984. This
                                                      photograph shows an ice jam on the Meade River. The water in the river is flowing from left
                                                      to right. Notice how the large pan of channel ice on the downstream side has caused the
                                                      smaller floating ice blocks to form an ice jam at this location.

                                                                                                                                               67

                                                                            V, 7 t,

                                                                                                                            T"

                                                                                                   t
                                       -IWO

                                         41

                                                                                                         '41

                                                                                                                                   77ql

                   Figure 41.
                   A low altitude oblique aerial photograph taken from a Cessna 182 on 10 June 1984. This
                   view is looking upstream (south) along the Meade River. The photograph shows a large ice
                   jam on the river that has backed up water onto flood unit 2 areas that are in the immediate
                   upstream area of the ice jam. No flood unit 2 areas are flooded downstream of this ice jam.
                   Notice how the ice in the river has been blocked by the channel ice on the left side of the
                   front of the ice jam.

                   68

                                                                               K,

                                                                                _2k

                                                                                             2

                    MEADE A.C.M.S. No.1-
                    LZ
                                                        Figure 42.
                                                        A low altitude black and white aerial photograph taken by the U.S. Navy in 1948. This
                                                        photograph is showing the geomorphic (physiographic) floodplain units and the corres-
                                                        ponding flood potential units along a part of the Meade River. I is flood unit I (the active
                                                        channel), 2 is flood unit 2, 3 is flood unit 3, 4 is flood unit 4 and 6 is non-flood unit 6 (also see
                                                        Figures 43 and 44). Meade A.C.M.S. No. I is an Active Channel Material Sample site, see Map
                                                        2b and Appendix D. The scene is 3.5 km. (2.2 mi.) across. U.S. Navy (BAR), Roll number 269,
                                                        frame number 55, 1948.

                                                                                                                                                   69

                                                   -OVA

                                                    -M

                   Figure 43.
                   A very low altitude oblique aerial photograph taken from a Belt 206 helicopter on 2 August
                   1984. This photograph shows three potential flood units along the Meade River of Figure
                   42. The river is flowing from right to left. I is flood unit I (the active channel), 3 is flood unit
                   3 and 4 is flood unit 4. Notice the definite physiographic break between flood units 3 and 4.

                   70

                                                                                                      @Z_

                                                         Figure 44.
                                                         A very low altitude oblique aerial photograph taken from a Bell 206 helicopter on 2 August
                                                         1984. This photograph shows the relationship of flood unit 3 and non-flood unit 6 along the
                                                         Meade River of Figure 42. The river is flowing from right to left. Flood unit 3 is 4.9 meters
                                                         (16 ft.) above the present low discharge level of the river. Non-flood unit 6 is 8.2 meters (27
                                                         ft.) above the present low discharge level of the river. Notice the definite physiographic
                                                         break between flood unit 3 and non-flood unit 6. Location "A!' in this photograph (see
                                                         Figure 45) has water scoured peat beds (that underly the tundra mat) and driftwood that
                                                         indicates a former high flood water level of the Meade River,

                                                                                                                                                      71

                                                                                               Z .0

                   -7                                                 X

                                                                            J It

                             r -;&0,

                                                                                                  A,

                   Figure 45.
                   A photograph taken from the ground on 2 August 1984 of location "A:' of Figure 44. This
                   photograph shows water scoured peat beds and driftwood 4.9 meters (16 ft.) above the
                   present water level of the Meade River. Also see Figures 42 and 44.

                   72

                                                                                                            W

                                                             A

                                                      Figure 46.
                                                      A %,-cry IOWaltitUde oblique aerial photograph taken from a Bell 206 helicopter on 2 August
                                                      1984. This photograph shows a bar ("A:') of gravel, cobbles and boulders in the Mcade River
                                                      channel. These bars are localized features that occur on1v where the river has Cut into the
                                                      underlying Cretaceous in age bedrock. Also see Figure 45.

                                                                                                                                                73

                                                                                                             -5-

                                                               7 Na-

                                                      B

                                                 :5@-"2 3-44T

                                                                                               MZ!,

                  Figure 47.
                  A very low attitude oblique aerial photograph taken from Bell 206 helicopter on 2 August
                  1984. This photograph shows a closeup ofthe bar ofFigure 46. "B" is inplace Cretaceous in
                  age bedrock, "A:' is gravel, cobbles and boulders derived from the bedrock.

                  74

                                                      Usuktuk River

                                                              The Usuktuk River is located on the Meade River and Lookout Ridge
                                                      1:250,000 USGS quadrangle maps. The flooding units of the Usuktuk River are
                                                      shown on Maps 2a and 2b. A total of 46.0 miles of the Usuktuk River active channel
                                                      was mapped from the junction with the Meade River (Appendix A). The Usuktuk
                                                      River has a watershed area of 622.0 square miles (Table 3). It is a meandering, slightly
                                                      incised stream (Table 7).
                                                              Spring breakup starts with water flowing over a channel with only small
                                                      amounts of ice in it. Localized flooding caused by ice jams is a minor to moderate
                                                      flooding hazard on the Usuktuk River.

                                                              Map Flood Units, Usuktuk River
                                                              I = low magnitude - high frequency flooding:
                                                      Physiographically the lowest active floodplain unit which is covered by water every
                                                      year. This unit is the active channel which exhibits annual change and is bare of
                                                      vegetation.
                                                              2 = intermediate magnitude - intermediate frequency flooding:
                                                      There is not a sharp physiographic break between flood units I and 2. Flood unit 2 is
                                                      mainly covered with grasses with some groves of low willows. This unit shows the
                                                      effects of recent erosion and deposition by running water. Eolian sand dunes may be
                                                      common in places. The estimated flooding frequency is 3 to 10 years.
                                                              3 = high magnitude - low frequency flooding:
                                                      This unit is physiographically higher than flood unit 2. There is a gradational to
                                                      definite physiographic break between units 2 and 3. Unit 3 shows the scars of
                                                      running water but has a good cover of tundra and some grasses. Vegetated eolian sand
                                                      dunes may be common in places. It has minor permanent ice features such as
                                                      polygons and patterned ground. The estimated flooding frequency is 10 to 50 years.
                                                              4 = rarely floods, very high magnitude - very low frequency flooding:
                                                      This flooding unit is physiographically the highest active floodplain. There is a
                                                      definite physiographic break between this flood unit and flood unit 3. This unit has a
                                                      well established cover of tundra. Flood unit 4 shows the old scars of running water.
                                                      This unit strongly exhibits the features of an ice-rich, permanently frozen material.
                                                      Such features as patterned ground, high and low centered polygons, and poor
                                                      drainage characterize this unit. Contains vegetated eolian sand dunes. The estimated
                                                      flooding frequency is 50 to 100 vears.
                                                              5 = no flooding:
                                                      There is no physiographic break between flood units 5 and 4. Flood unit 5 is probably
                                                      at the limit of the Project Flood. It has the same geornorphology as unit 4.
                                                              6 = high floodplain terrace or eolian dune on the floodplain, no flooding:
                                                      This unit is physiographically higher than flooding units 4 and 5 and there is a
                                                      definite physiographic break 'between non-flood unit 6 and units 4 and 5.

                                                                                                                                        75

                                                     Ivisaruk River

                                                              The Ivisaruk River is located on the Wainwright and Utukok River
                                                     1:250,000 USGS quadrangle maps. The flooding units of the Ivisaruk River are
                                                     shown on Maps 4a and 4b. A total of 56.0 miles of the Ivisaruk River active channel
                                                     was mapped from Neakok Island (Kuk River) to the 100 foot topographic contour
                                                     (Appendix A). The Ivisaruk River has a watershed area of 522.0 square miles (Table
                                                     3). It is an incised meandering stream that is slightly entrenched (Table 7). It has a
                                                     gradient of 1.8 feet permile (Table 2, Appendix C, Figure 49). The IvisarukRiver has a
                                                     narrow, confined delta where it empties into the Kuk River estuary.
                                                              Spring breakup starts with water flowing over the channel ice. Localized
                                                     flooding caused by ice jams is a minor to moderate flooding hazard on the Ivisaruk
                                                     River (see Figures 24 and 25).

                                                              Map Flood Units, lvisaruk River
                                                              I = low magnitude - high frequency flooding:
                                                     Physiographically the lowest active floodplain unit which is covered by water every
                                                     year. This unit is the active channel which exhibits annual change and is bare of
                                                     vegetation.
                                                              2 = intermediate magnitude - intermediate frequency flooding:
                                                     There is not a sharp physiographic break between flood units I and 2. Flood unit 2 i;
                                                     mainly covered with grasses with some groves of low willows. This unit shows the
                                                     effects of recent erosion and deposition by running water. The estimated flooding
                                                     frequency is 3 to 10 years.
                                                              3 = high magnitude - low frequency flooding:
                                                     This unit is physiographically higher than flood unit 2. There is a definite
                                                     physiographic break between units 2 and 3. Unit 3 shows the scars of running water
                                                     but has a good cover of tundra and some grasses. It has permanent ice features such as
                                                     polygons and patterned ground. The estimated flooding frequency is 2 5 to 5 0 years.
                                                              4 = rarely floods, very high magnitude - very low frequency flooding:
                                                     This flooding unit is physiographically the highest active floodplain. There is a
                                                     gradational to definite physiographic break between this flood unit and unit 3. This
                                                     unit has a well established cover of tundra. This unit strongly exhibits the features of
                                                     an ice-rich, permanently frozen material. Such features as patterned ground and high
                                                     and low centered polygons. The estimated flooding frequency is 50 to 100 years.
                                                     Flood unit 4 areas may flood in the delta area during a Chukehi Sea storm 'surge,
                                                     especially if the surge coincides with a period of high river discharge.
                                                              5 = high floodplain terrace, no flooding:
                                                     This unit is physiographically higher than flooding unit 4 and there is a definite
                                                     physiographic break between non-flood unit 5 and unit 4.

                                                                                                                                           77

                                                       Kuk River

                                                                 The Kuk River is located on the \Vainwright 1:250,000 USGS quadrangle
                                                       map. The flooding units of the Kuk River are shown on maps 4a and 4b. A total of 43.5
                                                       miles of the Kuk River estuary and active channel was mapped from the Chukchi Sea
                                                       to the Avalik River (Appendix A). The Kuk River has the second largest watershed
                                                       area, 4,275.0 square miles (Table 3), of the rivers studied in this investigation. It is an
                                                       estuarine stream for 25 miles from the Chukchi Sea to its confined delta, and is
                                                       slightly meandering and slightly entrenched upstream of its confined delta (Table 7).
                                                       The Kuk/Avalik River system has a gradient of 0.9 feet per mile upstream of the Kuk
                                                       River estuary (Table 2, Appendix C, Figures 49 and 51).
                                                                 Spring breakup starts with water flowing over the channel ice. Localized
                                                       flooding caused by ice jams is a minor to moderate flooding hazard on the Kuk River
                                                       (see Figures 24 and 25).
                                                                 Childers (1979) has estimated that the Kuk River has a bankfull channel
                                                       dischargeas itenters the estuary of 1,603 M3/sec. (56,600 ft.3/sec.)anda 50 yearflood
                                                       discharge of 2,860 M3/sec. (101,000 ft.    3/sec.). The mean annual precipitation of the
                                                       river basin is 25 cm. (10 in.).

                                                                 Map Flood Units, Kuk River
                                                                 I = low magnitude - high frequency flooding:
                                                       Physiographically the lowest active floodplain unit which is covered by water every
                                                       year. This unit is the active channel which exhibits annual change and is bare of
                                                       vegetation.
                                                                 2 = intermediate magnitude - intermediate frequency flooding:
                                                       There is not a sharp physiographic break between flood units I and 2. Flood unit 2 is
                                                       mainly covered with grasses with some groves of willows. This unit shows the
                                                       effects of recent erosion and deposition by running water. Eolian sand dunes may be
                                                       common in places. The estimated flooding frequency is 3 to 10 years.
                                                                 3 = high magnitude - low frequency flooding:
                                                       This unit is physiographically higher tha*n flood unit 2. There is a definite
                                                       physiographic break between this flood unit and flood unit 2. This unit has a well
                                                       established cover of tundra. it strongly exhibits the features of an ice-rich, perma-
                                                       nently frozen material. Such features as patterned ground and high and low centered
                                                       polygons characterize this unit. Contains vegetated eolian sand dunes. The estimated
                                                       flooding frequency is 10 to 25 years.
                                                                 4 = rarely floods, very high magnitude - very low frequency flooding:
                                                       This flooding unit is physiographically the highest active floodplain. There is a
                                                       gradational physiographic break between this flood unit and unit 3. This unit has a
                                                       well established cover of tundra. Such features as patterned ground and high and low
                                                       centered polygons characterize this unit. Contains vegetated eolian sand dunes. The
                                                       estimated flooding frequency is 50 to 100 years.
                                                                 5 = high floodplain terrace, no flooding:
                                                       This unit is physiographically higher than flooding unit 4 and there is a definite
                                                       physiographic break between non-flood unit 5 and unit 4.

                                                                                                                                                79

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                                                                                   1,:',
                                                                                    @
                                                           1Y

                                                                                                                                                   MI

                                                                                                                                                6@

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                                                                                                                                                4@
                                                                                                                                                "W"

                 Figure 48.
                 A very low altitude oblique aerial photograph taken from a Bell 206 helicopter on 2 August
                 1984. This photograph shows a strandline of driftwood deposited by an ocean storm surge
                 on the coast of the Chukchi Sea 18 km. (11 mi.) northeast of Peard Bay. Ocean storm surges
                 may flood areas along the coast that are three meters (10 ft.) or less above normal sea level.

                 80

                                                     Kaolak River

                                                              The Kaolak River is located on the Wainwright and Utukok River 1:250,000
                                                     USGS quadrangle maps. The     flooding units of the Kaolak River are shown on Map 4b.
                                                     A total of 45.2 miles of the Kaolak River active channel was mapped from the
                                                     junction with the Avalik River to the 100 foot topographic contour (Appendix A).
                                                     The Kaolak River has a watershed area of 7/ 36.0 square miles (Table 3). It is an incised
                                                     meandering stream that is slightly entrenched (Table 77). It has a gradient of 2.3 feet
                                                     per mile (Table 2, Appendix C, Figures 49 and 51).
                                                              Spring breakup starts with water flowing over the channel ice. Localized
                                                     flooding caused by ice jams is a minor to moderate flooding hazard on the Kaolak
                                                     River. Recent flood levels along the Kaolak River as high as six meters (20 ft.) were
                                                     observed during the spring breakup in June 1948 (Hopkins and others, 1978).

                                                              Map Flood Units, Kaolak River
                                                              I = low magnitude - high frequency flooding:
                                                     Physiographically the lowest active floodplain unit which is covered by water every
                                                     year. This unit is the active channel which exhibits annual change and is bare of
                                                     vegetation.
                                                              2 = intermediate magnitude - intermediate frequency flooding:
                                                     There is not a sharp physiographic break between flood units I and 2. Flood unit 2 is
                                                     mainly covered with grasses with some groves of low willows. This unit shows the
                                                     effects of recent erosion and deposition by running water. The estimated flooding
                                                     frequency is 3 to 10 years.
                                                              3 = high magnitude - low frequency flooding:
                                                     This unit is physiographically higher than flood unit 2. There is a definite
                                                     physiographic break between units 2 and 3. Unit 3 shows the scars of running water
                                                     but has a good cover of tundra and some grasses. It has permanent ice features such as
                                                     polygons and patterned ground. The estimated flooding frequency is 10 to 25 years.
                                                              4 = rarely floods, very high magnitude - very low frequency flooding:
                                                     This flooding unit is physiographically the highest active floodplain. There is a
                                                     gradational to definite physiographic break between this flood unit and unit 3. This
                                                     unit has a well established cover of tundra. This unit strongly exhibits the features of
                                                     an ice-rich, permanently frozen material. Such features as patterned ground and high
                                                     and low centered polygons. The estimated flooding frequency is 50 to 100 years.
                                                              5 = high floodplain terrace, no flooding:
                                                     This unit is physiographically higher than flooding unit 4 and there is a definite
                                                     physiographic break between non-flood unit 5 and unit 4.

                                                                                                                                             81

                                                     Ketik River

                                                              The Ketik River is located on the Wainwright and Utukok River 1:250,000
                                                     USGS quadrangle maps. The flooding units of the Ketik River are shown on Maps 4c
                                                     and 4d. A total of 61.5 miles of the Ketik River active channel was mapped from the
                                                     junction with the Avalik River to the 100 foot topographic contour (Appendix A).
                                                     The Ketik River has a watershed area of 721.0 square miles (Table 3). It is an incised
                                                     meandering stream that is slightly entrenched (Table 7). It has a gradient of 1.6 feet
                                                     per mile (Table 2, Appendix C, Figures 49 and 51).
                                                              Spring breakup starts with water flowing over the channel ice. Localized
                                                     flooding caused by ice jams is a minor to moderate flooding hazard on the Ketik
                                                     River. Recent flood levels along the Ketik River as high as six meters (20 ft.) were
                                                     observed during the spring breakup in June 1948 (Hopkins and others, 1978).

                                                              Map Flood Units, Ketik River
                                                              I = low magnitude - high frequency flooding:
                                                     Physiographically the lowest active floodplain unit which is covered by water every
                                                     year. This unit is the active channel which exhibits annual change and is bare of
                                                     vegetation.
                                                              2 = intermediate magnitude - intermediate frequency flooding:
                                                     There is not a sharp physiographic break between flood units I and 2. Flood unit 2 is
                                                     mainly covered with grasses with some groves of low willows. This unit shows the
                                                     effects of recent erosion and deposition by running water. The estimated flooding
                                                     frequency is 3 to 10 years.
                                                              3 = high magnitude - low frequency flooding:
                                                     This unit is physiographically higher than flood unit 2. There is a definite
                                                     physiographic break between units 2 and 3. Unit 3 shows the scars of running water
                                                     but has a good cover of tundra and some grasses. It has permanent ice features such as
                                                     polygons and patterned ground. The estimated flooding frequency is 10 to 25 years.
                                                              4 = rarely floods, very high magnitude - very low frequency flooding:
                                                     This flooding uni't is physiogr'aphically the highest active floodplain. There is a
                                                     gradational to definite physiographic break between this flood unit and unit 3. This
                                                     unit has a well established cover of tundra. This unit strongly exhibits the features of
                                                     an ice-rich, permanently frozen material. Such features as patterned ground and high
                                                     and low centered polygons. The estimated flooding frequency is 50 to 100 years.
                                                              5 = high floodplain terrace, no flooding:
                                                     This unit is physiographically higher than flooding unit 4 and there is a definite
                                                     pbysiographic break between non-flood unit 5 and unit 4.

                                                                                                                                           83

                                                     Avalik River

                                                             The Avalik River is located on the Wainwright, Meade River and Lookout
                                                     Ridge 1:250,000 quadrangle maps. The flooding units of the A-*,-alik River are shown
                                                     on Maps 4b and 4c. A total of 64.3 miles of the ANalik River active channel was
                                                     mapped from the Kuk River to the 100 foot topographic contour (Appendix A). The
                                                     Avalik River has a watershed area of 1,197.0 square miles (Table 3). It is an incised
                                                     meandering stream that is slightly entrenched (Table 7). It has a gradient of 0.9 feet
                                                     per mile (Table 2, Appendix C, Figures 49 and 51).
                                                           . Spring breakup starts with water flowing over the ice. Localized flooding
                                                     caused by ice jams is a minor to moderate flooding hazard on the Avalik River.

                                                             Map Flood Units, Avalik River
                                                             I = low magnitude - high frequency flooding:
                                                     Physiographically the lowest active floodplain unit which is covered by water every
                                                     year. This unit is the active channel which exhibits annual change and is bare of
                                                     vegetation.
                                                             2 = intermediate magnitude - intermediate frequency flooding:
                                                     There is not a sharp physiographic break between flood units I and 2. Flood unit 2 is
                                                     mainly' covered with grasses with some groves of willows. This unit shows the
                                                     effect's of recent erosion and deposition by running water. Eolian sand dunes may be
                                                     common in places. The estimated flooding frequency is 3 to 10 years.
                                                             3 = high magnitude - low frequency flooding:
                                                     This unit is physiographically higher than flood unit 2. There is a definite
                                                     physiographic break between this flood unit and flood unit 2. This unit has a well
                                                     established cover of tundra. It strongly exhibits the features of an ice-rich, perma-
                                                     nentlv frozen material. Such features as patterned ground and high and low centered
                                                     polygons characterize this unit. Contains vegetated eolian sand dunes. The estimated
                                                     flooding frequency is 10 to 25 years.
                                                             4 = rarelv floods, very high magnitude - very low frequency flooding:
                                                     This flooding uni't is physiographically the highest active floodplain. There is a
                                                     gradational physiographic break between this flood unit and flood unit 3. This unit
                                                     has a well established cover of tundra. Such features as patterned ground and high
                                                     and low centered polygons characterize this unit. Contains vegetated eolian sand
                                                     dunes. The estimated flooding frequency is 50 to 100 years.
                                                             5 = high floodplain terrace, no flooding:
                                                     This unit is physiographically higher than flooding unit 4 and there is a definite
                                                     physiographic break between non-flood unit 5 and unit 4.

                                                                                                                                        85

                                                   Kugrua River

                                                            The Kugrua River is one of four rivers of this investigation that has its
                                                   watershed completely within the Teshekpuk section of the Arctic Coastal Plain
                                                   province (Figure 3). The other three rivers are the Ongorakvik, Nokotlek and the
                                                   Tunalik Rivers. All four of these rivers have a simple three stage flooding frequency
                                                   (Table4), The Kugrua River is located on the Wainwright and Meade River 1:250,000
                                                   USGS quadrangle maps, The flooding units of the Kugrua River are shown on Map 3.
                                                   A total of 39.0 miles of the Kugrua River active channel was mapped from Kugrua Bay
                                                   to the 75 foot topographic contour (Appendix A). The Kugrua River has a watershed
                                                   area of 318.0 square miles (Table 3). It is a meandering incised stream with no delta
                                                   (Table 7). It has a gradient of 1.9 feet per mile (Table 2, Appendix C, Figure 49). The
                                                   localized flooding caused by ice jams is a minor flooding hazard on the Kugrua River.

                                                            Map Flood Units, Kugrua River
                                                            I = low magnitude - high frequency flooding:
                                                   Physiographically the lowest active floodplain unit which is covered by water every
                                                   year. This unit is the active channel which exhibits annual chan e and is bare of
                                                                                                                        9
                                                   vegetation.
                                                            2 = intermediate magnitude - intermediate frequency flooding:
                                                   There is not a sharp physiographic break between flood units I and 2. Flood unit 2 is
                                                   mainly covered with grasses with some low willows. This unit shows the effects of
                                                   recent erosion and deposition by running water. The estimated flooding frequency is
                                                   three to seven years.
                                                            3 = high magnitude - low frequency flooding:
                                                   This unit is physiographically higher than flood unit 2 and it is the highest active
                                                   floodplain. There is a definite physiographic break between this flood unit and flood
                                                   unit 2. This unit has a well established cover of tundra. It strongly exhibits the
                                                   features of an ice-rich, permanently frozen material. Such features as patterned
                                                   ground and high and low centered polygons characterize this unit. The estimated
                                                   flooding frequency is five to 50 years.

                                                                                                                                        87

                                                      Ongorakvik River

                                                               The Ongorakvik River is the smallest river that was mapped in this
                                                      investigation. It is located on the Wainwright 1:250,000 USGS quadrangle map. The
                                                      flooding units of the Ongorakvik River are shown on Map 5. A total of 16.5 miles of
                                                      the Ongorakvik River active channel was mapped from Kasegaluk Lagoon to the 50
                                                      foot topographic contour (Appendix A). The Onogorakvik River has a watershed
                                                      area of 73.0 square miles (Table 3). It is a straight to slightly meandering stream (Table
                                                      7). It has the highest gradient of all the rivers mapped in this investigation of 6.1 feet
                                                      per mile (Table 2, Appendix C, Figure 49).

                                                               Map Flood Units, Ongorakvik River
                                                               I = low magnitude - high frequency flooding:
                                                      Physiographically the lowest active floodplain unit which is covered by water every
                                                      year. This unit is the active channel which exhibits annual change and is bare of
                                                      vegetation.
                                                               2 = intermediate magnitude - intermediate frequency flooding:
                                                      There is not a sharp physiographic break between flood units I'and 2. Flood unit 2 is
                                                      mainly covered with grasses with some low willows. This unit shows the effects of
                                                      recent erosion and deposition by running water. The estimated flooding frequency is
                                                      three to seven years.
                                                               3 = high magnitude - low frequency flooding:
                                                      This unit is physiographically higher than flood unit 2 and it is the highest active
                                                      floodplain. There is a definite physiographic break between this flood unit and flood
                                                      unit 2. This unit has a well established cover of tundra. It strongly exhibits the
                                                      features of an ice-rich, permanently frozen material. Such features as patterned
                                                      ground and high and low centered polygons characterize this unit. The estimated
                                                      flooding frequency is five to 50 years.

                                                                                                                                               89

                                                      Nokodek River

                                                               The Nokotlek River is located on the Wainwright 1: 2 5 0, 000 USGS quadran-
                                                      gle map. The flooding units of the Nokotlek River are shown on Map 5. A total of 18.0
                                                      miles of the Nokotlek River active channel was mapped from Kasegaluk Lagoon to
                                                      the 50 foot topographic contour (Appendix A). The Nokotlek River has a watershed
                                                      area of 105.0 square miles (Table 3). It is a straight to slightly meandering incised
                                                      stream (Table 7). It has a gradient of 2.8 feet per mile (Table 2, Appendix C, Figure 49).

                                                               Map Flood Units, Nokotlek River
                                                               I = low magnitude - high frequency flooding:
                                                      Physiographically the lowest active floodplain unit which is covered by water every
                                                      year. This unit is the active channel which exhibits annual chan e and is bare If
                                                                                                                              9
                                                      vegetation.
                                                               2 = intermediate magnitude - intermediate frequency flooding:
                                                      There is not a sharp physiographic break between flood units I and 2. Flood unit 2 is
                                                      mainly covered with grasses with some low willows. This unit shows the effects of
                                                      recent erosion and deposition by running water. The estimated flooding frequency is
                                                      three to seven years.
                                                               3 = high magnitude - low frequency flooding:
                                                      This unit is physiographically higher than flood unit 2 and it is the highest active
                                                      floodplain. There is a definite physiographic break between this flood unit and flood
                                                      unit 2. This unit has a well established cover of tundra. It strongly exhibits the
                                                      features of an ice-rich, permanently frozen material. Such features as patterned
                                                      ground and high and low centered polygons characterize this unit. The estimated
                                                      flooding frequency is five to 50 years.

                                                                                                                                               91

                                                    Tunalik River

                                                             The Tunalik River is located on the Wainwright 1:250,000 USGS quadrangle
                                                    map. The flooding units of the Tunalik River arc shown on Map 5. A total of 27.5 miles
                                                    of the Tunalik River active channel was mapped from Avak Inlet to the 100 foot
                                                    topographic contour (Appendix A). The Tunalik River has a watershed area of 145 .0
                                                    square miles (Table 3). It is a straight to slightly meandering incised stream that is
                                                    slightly entrenched (Table 7). It has a gradient of 3.6 feet per mile (Table 2, Appendix
                                                    C, Figure 49).

                                                             Map Flood Units, Tunalik River
                                                             I = low magnitude - high frequency flooding:
                                                    Physiographically the lowest active floodplain unit which is covered by water everN
                                                    year. This unit is the active channel which exhibits annual chan e and is bare of
                                                                                                                           9
                                                    vegetation.
                                                             2 = intermediate magnitude - intermediate frequency flooding:
                                                    There is not a sharp physiographic break between flood units I and 2. Flood unit 2 is
                                                    mainly covered with grasses with some low willows. This unit shows the effects of
                                                    recent erosion and deposition by running water. The estimated flooding frequency is
                                                    three to seven years.
                                                             3 = high magnitude - low frequency flooding:
                                                    This unit is phvsiographically higher than flood unit 2 and it is the highest active
                                                    floodplain. There is a definite physiographic break between this flood unit and flood
                                                    unit 2. This unit has a well established cover of tundra. It strongly exhibits the
                                                    features of an ice-rich, permanently frozen material. Such features as patterned
                                                    ground and high and low centered polygons characterize this unit. The estimated
                                                    flooding frequency is five to 50 years.

                                                                                                                                            93

                                                      Summary of Conclusions

                                                              This study supports the supposition that the rivers of Arctic Alaska are
                                                      unique, and their features and behavior cannot be expected to reflect data from river
                                                      studies in subarctic and temperate areas.
                                                              The flooding units mapped in this investigation are defined by physio-
                                                      graphic features. These units represent the field evidence for certain flooding events.
                                                      However it must be kept in mind that flooding which occurs at breakup may be the
                                                      largest flooding event. But, flooding at breakup may have the least physical effect
                                                      because the ground is mostly still frozen at that time.
                                                              The Arctic Coastal Plain that these rivers flow across is verv flat. Thus, the
                                                      rivers may be expected to respond to even a small local change in t@e earth's crust.
                                                      The Chipp, Topagoruk and Meade Rivers appear to be responding to tectonic
                                                      subsidence in the Dease Inlet/Admiralty Bay area. The active subsidence in this area
                                                      may explain the existence of the large embayment of Dease Inlet/Admiralty Bay into
                                                      the Arctic Coastal Plain.
                                                              The Arctic rivers of this investigation have a generally later spring breakup
                                                      than the rivers of the previous two studies. This area where the river watersheds are
                                                      restricted to the Arctic Coastal Plain and the northern section of the Arctic Foothills
                                                      physiographic province is designated the Barrow River Basin.
                                                              A significant difference between the rivers of this study and the rivers of
                                                      Floodplain Study number I is the lack of aufeis. Aufeis causes the temporary
                                                      damming of a river, producing localized flooding. Though ice-block damming is a
                                                      major flooding hazard along the Meade River, no aufeis occurred along the rivers of
                                                      this investigation.
                                                              The process of talik lake breaching on the Chipp River is a major flooding
                                                      hazard to permanent facilities built adjacent to the river.

                                                                                                                                           95

                                                                                  References Cited

                                                   Cannon, P.J., 1983, Floodplain Mapping of Rivers Along the Chukchi Sea/Arctic
                                                             Ocean Coastal Plain; North Slope Borough Coastal Management
                                                             Program, Floodplain Studies Report No. 2.
                                                   Carter, L.D., 1981, A Pleistocene Sand Sea on the Alaskan Arctic Coastal Plain,
                                                             Science, 23 January 1981, Vol. 211, PP 381-383.
                                                   Carter, L.D., 1983, Engineering-Geologic Maps of Northern Alaska, Teshekpuk
                                                             Quadrangle, U.S.G.S. Open-File Report 83-634.
                                                   Childers, J.M., Kernodle, D.R., and Loeffler, R.M., 1979, Hydrologic
                                                             Reconnaissance of Western Arctic Alaska, 1976 and 1977, U.S.G.S.
                                                             Open-File Report 79-699.
                                                   Chov, Ven Te, 1964, Handbook of Applied Hydrology, McGraw-Hill Book Co.,
                                                             New York.
                                                   Dingman, S.L., 1975, Hvdrologic Effects of Frozen Ground, U.S. Army Corps of
                                                             Engineers, Cold Regions Research and Engineering Laboratory, Special
                                                             Report No. 218.
                                                   Hopkins, D.M., Hartz, RAX@, and Robinson, S.W., 1978, Record of a Prehistoric
                                                             Storm Surge in the Wainwright Inlet-Kuk River Area, U.S.G.S. Circular
                                                             804-B, pp B-29 to B-31.
                                                   Leopold, L.B., and Dunne, T., 1978, Water in Environmental Planning, W.H.
                                                             Freeman and Co., San Francisco.
                                                   Mortensen, T.W., 1982, The Flooding Potential and Geomorphology of Five
                                                             Selected Arctic Rivers, Arctic Coastal Plain, Alaska. Master of Science
                                                             Thesis, University of Alaska, Fairbanks, Alaska, May 1982.
                                                   Mortensen, T.W., and Cannon, P.J., 1982, Flood Hazard Potential of Five Selected
                                                             Arctic Rivers, Arctic Coastal Plain, Alaska; North Slope Borough Coastal
                                                             Management Program, Floodplain Studies Report No. 1.
                                                   Wahrhaftig, C., 1965, Physiographic Divisions of Alaska, U.S.G.S. Professional
                                                             Paper 482.
                                                   Williams, J.R., Yeend, W.E., Carter, L.D., and Hamilton, T.D., 1977, Preliminary
                                                             Surficial Deposits Map of National Petroleum Reserve-Alaska, U.S.G.S.
                                                             Open-File Report 77-868.
                                                   Williams, J.R., Carter, L.D., Yeend, WE., 19-178, Coastal Plain Deposits of NPR-A,
                                                             U.S.G.S. Circular 772-B, pp B-20 to B-22.
                                                   Williams, J.R., 1983a, Engineering-Geologic Maps of Northern Alaska, Meade
                                                             River Quadrangle, U.S.G.S. Open-File Report 83-294.
                                                   Williams, J.R., 1983b, Engineering-Geologic Maps of Northern Alaska, Wainwright
                                                             Quadrangle, U.S.G.S. Open-File Report 83-457.
                                                   Wolman, M.G., 1971, Evaluating Alternate Techniques of Floodplain Mapping,
                                                             Water Resources Research, Vol. 7, No. 6, pp 1383-1392.
                                                   Yeend, WE., 1983, Engineering-Geologic Maps of Northern Alaska, Lookout
                                                             Ridge Quandrangle, U.S.G.S. Open-File Report 83-279.

                                                                                                                                     97

                                                                 Appendix A. List of the Channel Miles of the 18 Rivers Mapped.

                                                       lkpikpuk River; 268.3 miles of active channel from Smith Bay to Maybe Creek/Kigalik
                                                       River junction, including distributary channels.

                                                       Meade River; 212.4 miles of active channel from Admiralty Bay to the 200 foot contour,
                                                       including distributary channels.

                                                       Topagoruk River; 115.5 miles of active channel from Admiralty Bay to the 100 foot
                                                       contour, including distributary channels.

                                                       Avalik River; 63.4 miles of active channel from the Kuk River to the 100 foot contour.

                                                       Chipp River; 62.0 miles of active channel from Admiralty Bay to the junction with the
                                                       lkpikpuk River.

                                                       Ketik River; 61.5 miles of active channel from the junction with the Avalik River to the 100
                                                       foot contour.

                                                       lvisarukRiver; 56.0 milesof active channel from Neakok Island (Kuk River)to the 100 foot
                                                       contour.

                                                       Usuktuk River; 46.0 miles of active channel from the junction with the Meade River.

                                                       Kaolak River; 45.2 miles of active channel from the junction with the Avalik River to the
                                                       100 foot contour.

                                                       AlaktakRiver; 43.5 miles of active channel from Pittalukruak Lake to the junctionwith the
                                                       lkpikpuk River.

                                                       Kuk River; 42.5 miles of estuary and active channel from the Chukchi Sea to the Avalik
                                                       River.

                                                       Oumalik River; 40.0 miles of active channel from the junction with the Chipp River to the
                                                       75 foot contour.

                                                       Kugrua River; 39.0 miles of active channel from Kugrua Bay to the 75 foot contour.

                                                       Tunalik River; 27.5 miles of active channel from Avak Inlet to the 100 foot contour.

                                                       Miguakiak River; 20.3 miles of active channel from Teshekpuk Lake to. the junction with
                                                       the lkpikpuk River.

                                                       Nokotlek River; 18.0 miles of active channel from Kasegaluk Lagoon to the 50 foot
                                                       contour.

                                                       Ongorakvik River; 16.5 miles of active channel from Kasegaluk Lagoon to the 100 foot
                                                       contour.

                                                       Piasuk River; 13 .0 miles of flood unit I from Smith Bay.

                                                       Grand total = 1,190.6 miles of active and active distributary channels mapped.

                                                                                                                                                 99

                                                                             Appendix B: Sources of Mapping Data

                                                      Map la: Flood Hazard Potential of the Ikpikpuk, Chipp, Alaktak, Miguakiak,
                                                               Piasuk and Topagoruk Rivers.

                                                      Maps
                                                      USGS 1:250,000 Topographic Map: Teshekpuk Quadrangle
                                                      USGS 1:63,360 Topographic Maps: Teshekpuk: C-2, C-3, C-4, C-5, D-2, D-3, D-4, D-5
                                                      Carter, L. David (1983) Engineering-Geologic Maps of Northern Alaska, Teshekpuk Quad-
                                                           rangle. USGS Open File Report 83-634.
                                                      Williams, John R. and Others (1977) Preliminary Surficial Deposits Map of NPR-A. USGS
                                                           Open File Report 77-868.
                                                      Beikman, H.M. and Lathram, E.H. (1976) Preliminary Geologic Map of Northern Alaska.
                                                           USGS Miscellaneous Field Studies Map MF-789.

                                                      Remote Sensing Data
                                                      1) Ikpikpuk, Chipp, Alaktak, Miguakiak and Piasuk Rivers
                                                      NASA Color Infrared Aerial Photography: NASA/jSC 364, July 1977
                                                           Roll 23, Frame Numbers: 30, 31, 32, 33, 34, 35, 36, 37, 38.
                                                      NASA Color Infrared Aerial Photography: Alaska 60 CIR, July 1979
                                                           Roll 2790, Frame Numbers: 3101, 3102, 3106, 3107, 3137, 3138, 3139, 3140, 3141,
                                                                                        3142, 3143, 3144, 3145, 3146, 3200, 3201, 3202, 3203,
                                                                                        3204, 3205, 3206, 3207, 3273, 3274, 3275, 3276,
                                                                                        3277,3278.
                                                      U.S. Navy Black & White Aerial Photography: BAR, 1948-1949
                                                           Roll 15, Frame Numbers: 74, 75, 76.
                                                           Roll 16, Frame Numbers: 126, 127, 128.
                                                           Roll 22, Frame Numbers: 30, 31, 32, 99, 100.
                                                           Roll 2 3, Frame Numbers: 8, 9, 10, 11, 12, 12, 3 2, 3 3, 15 3, 15 4, 15 5, 15 6, 163, 164, 165.
                                                           Roll 26, Frame Numbers: 28, 29, 30.
                                                      USGS Black & White Aerial Photography, August 19 5 5
                                                           Mission 57, Roll 106, Frame Numbers: 13733, 13734.
                                                      2) Topagoruk River
                                                      NASA Color Infrared Aerial Photography: NASA/JSC 364, July 1977
                                                           Roll 23, Frame Numbers: 38, 39, 40.
                                                      NASA Color Infrared Aerial Photography: Alaska 60 CIR, July 1979
                                                           Roll 2790, Frame Numbers: 3145, 3146, 3147, 3198, 3199, 3200, 3280, 3281, 3282.

                                                                                                                                          101

                                         Appendix B: Sources of Mapping Data

                  Landsat Satellite imagery Used for Map la
                  Date         Image Number         MSS Band

                  07/12/77           2902-21175            5
                  02/25/79         21495-21231             7
                  03/07/79         30367-21404             7
                  05/02/79         30423-21520             7
                  06/05/79         3057-2i4oi              7
                  05/16/81         22306-21372             7
                  05/29/83         40317-21422             4
                  05/16/84         50076-21342             7
                  06/01/84         50092-21344             7
                  06/08/84         50099-2i4to             7
                  06/08/84         @0099-214 10            5
                  06/10/84         50101-21284             5
                  o6/17/84         50108-21350             7
                  06/17/84         50108-21350             5
                  07/01/84         50122-21473             7
                  07/01/84         50122-21473             5

                  Map 1b: Flood Hazard Potential of the Ikpikpuk, Chipp, Oumalik and Topagoruk
                            Rivers.

                  Maps
                  USGS 1:250,000 Topographic Map: Teshekpuk Quadrangle
                  USGS 1: 2 50,000 Topographic Map: Meade River Quadrangle
                  USGS 1:63,360 Topographic Maps: Teshekpuk: A-2, A-3, A-4, A-5, B-2, B-3, B-4, B-5;
                                                     Meade River: A-1, B-I
                  Carter, L. David (1983) Engineering-Geologic Maps of Northern Alaska, Teshekpuk Quad-
                        rangle. USGS Open File Report 83-634.
                  Williams, John R. (1983) Engineering-Geologic Maps of Northern Alaska, Meade River
                        Quadrangle. USGS Open File Report 83-294.
                  Williams, John R. and Others (1977) Preliminarv Surficial Deposits Map of NPR-A. USGS
                        Open File Report 77-868.
                  Beikman, H.M. and Lathram, E.H. (1976) Preliminary Geologic Map of Northern Alaska.
                        USGS Miscellaneous Field Studies Map MF-789.

                  Remote Sensing Data
                  1) lkpikpuk and Chipp Rivers
                  NASA Color Infrared Aerial Photography: NASA/jSC 364, July 1977
                        Roll 23, Frame Numbers: 305, 306, 307@ 308, 309.
                  NASA Color Infrared Aerial Photography: Alaska 60 CIR, July 1979
                        Roll 2790, Frame Numbers: 3273, 3274, 3275, 3276, 3'277@ 3278.
                  NASA Color Infrared Aerial Photography: Alaska 60 CIR, July 1982
                        Roll 3101, Frame Numbers: 9605, 9606, 9607, 96@6, 9687, 9688, 9689, 9728, 9729,
                                                  97W 97311 9843, 9844, 9845.

                  102

                                                                            Appendix B: Sources of Mapping Data

                                                     Map 1b: continued
                                                     U.S. Navy Black & White Aerial Photography: BAR, 1948-1949
                                                           Roll 8, Frame Numbers: 175, 176, 177, 178, 179, 180, 181.
                                                           Roll 9, Frame Numbers: 7, 8, 9, 39, 40, 41, 42, 43, 52, 53, 54, 55, 56, 57.
                                                           Roll 17, Frame Numbers: 10, 11, 12, 13, 14, 15, 43, 44, 45.
                                                           Roll 26, Frame Numbers:   130, 131, 132, 133, 134, 135, 136, 137, 138.
                                                           Roll 29, Frame Numbers:   123, 124, 125, 144, 145, 146, 147, 198, 199, 200, 201.
                                                           Roll 31, Frame Numbers@   14, 15.
                                                           Roll 120, Frame Numbers: 67, 68, 69, 70, 82, 83, 84, 85, 86, 145, 146, 147, 148, 190,
                                                                                      191, 192, 193, 211, 212, 213.
                                                     2) Ournalik River
                                                     NASA Color Infrared Aerial Photography: NASA/jK 364, July 1977
                                                           Roll 23, Frame Numbers: 305, 306
                                                     NASA Color Infrared Aerial Photography: Alaska 60 CIR, July 1982
                                                           Roll 3101, Frame Numbers: 9610, 9611, 9726, 9727, 9845, 9846.
                                                     3) Topagoruk River
                                                     NASA Color Infrared Aerial Photography: NASA/JSC 364, July 1977
                                                           Roll 23, Frame Numbers: 300, 301.
                                                     NASA Color Infrared Aerial Photography: Alaska 60 CIR, July 1979
                                                           Roll 2790, Frame Numbers: 3280, 3281, 3282, 3339, @340.
                                                     NASA Color Infrared Aerial Photography: Alaska 60 CIR, August 1982
                                                           Roll 3101, Frame Numbers: 9614, 9615, 9695, 9696, 9697, 9721, 9722, 9723.
                                                     Landsat Satellite Imagery Used for Map I b
                                                     Date          Image Number         MSS Band
                                                     07/12/77           2902-21175            5
                                                     02/25/79         21495-21231             7
                                                     03/07/79         30367-214o4             7
                                                     06/05/79         30457-2i4ol             7
                                                     05/16/79         223o6-21372             7
                                                     05/29/83         40317-21422             4
                                                     05/16/84         50076-21342             7
                                                     06/08/84         50099-21410             7
                                                     06/08/84         50099-21410             5
                                                     06/17/84         50108-21350             7
                                                     06/17/84         50108-21350             5
                                                     07/01/84         50122-21473             7
                                                     07/01/84         50122-21473             5

                                                     Map I c: Flood Hazard Potential of the Ikpikpuk River

                                                     Maps
                                                     USGS 1:250,000 Topographic Map: Ikpikpuk River Quadrangle
                                                     USGS 1:50,000 Advance Proof Topographic Maps: lkpikpuk River: C-3, C-4, D-3, D-4

                                                                                                                                           103

                                        Appendix B: Sources of Mapping Data

                  Map 1c: continued
                  Williams, John R. and Others (1977) Preliminary Surficial Deposits Map of NPR-A. USGS
                       Open File Report 77-868.
                  Beikman, H.M. and Lathram, E.H. (1976) Preliminary Geologic Map of Northern Alaska.
                       USGS Miscellaneous Field Studies Map MF-789.

                  Remote Sensing Data
                  NASA Color Infrared Aerial Photography: Alaska 60 CIR, August 1980
                       Roll 2925, Frame Numbers: 8304, 8305.
                  NASA Color Infrared Aerial Photography: Alaska 60 CIR, July 1982
                       Roll 3101, Frame Numbers: 9659, 9660, 9686, 9687, 9688, 9689.
                  NASA Color Infrared Aerial Photography: Alaska 60 CIR, August 1982
                       Roll 3114, Frame Numbers: 986, 987, 988.
                  U.S. Navv Black & White Aerial Photography: BAR, 1948-1949
                       Roil 14, Frame Numbers:  14, 15, 16, 17, 18, 96, 97, 98, 154, 155, 156.
                       Roll 87, Frame Numbers:  139, 140, 141, 142, 143.
                  Landsat Satellite Imagery
                  Date         Image Number        MSS Band

                  07/12/77          2902-21175          5
                  02/25/79        21495-2 1231          7
                  03/07/79        30367-21404           7
                  06/05/79        30457-21401           7
                  05/16/81        22306-21372           7
                  05/29/83        40317-21424           4
                  06/10/84        50101-21290           7
                  06/17/84        50108-21352           7
                  06/17/84        50108-213 52          5

                  Map I d: Flood Hazard Potential of the lkpikpuk River.

                  Maps
                  USGS 1:250,000 lkpikpuk River Quadrangle
                  USGS 1:50,000 Advance Proof Topographic Maps: Ikpikpuk River: B-3, B-4, C-3, C-4
                  Williams, John R. and Others (1977) Preliminary Surficial Deposits Map of NPR-A. USGS
                       Open File Report 77-868.
                  Beikman, H.M. and Lathram, E.H. (1976) Preliminary Geologic Map of Northern Alaska,
                       USGS Miscellaneous Field Studies Map MF-789.

                  Remote Sensing Data
                  NASA Color Infrared Aerial Photography: NASA/JSC 364, August 1977
                       Roll 25, Frame Numbers: 166, 167, 168, 224, 225.
                  NASA Color Infrared Aerial Photography: Alaska 60 CIR, July 1979
                       Roll 2786, Frame Numbers: 2176, 2177, 2236, 2237, 2238.

                  104

                                                                               Appendix B: Sources of Mapping Data

                                                        Landsat Satellite Imagerx
                                                        Date          Image Number         MSS Band
                                                        06/11/76           2506-21340            -7
                                                        07/12/77           2902-21175            5
                                                        )5/16/81         22306-2 1372            -7
                                                        ()6/10/84        50101-21290
                                                        06/17/84         50108-2 1352            7
                                                        o6m -//84        50108-2 1352            5

                                                        Map 2a: Flood Hazard Potential of the Meade and Usuktuk Rivers.

                                                        Maps
                                                        USGS 1:250,000 Topographic Map: Meade River Quadrangle
                                                        USGS 1:250,000 Topographic Map: TeshckpLik Quadrangle
                                                        USGS 1:63,360'ropographic Maps: Meade River: C-1, C-2, C-3, D-1, D-2. D-3
                                                                                            Tcshekpuk: C-5, D-5
                                                        Williams, John R. (1983) Engineerin  g-Geologic Maps of Northern Alaska, Meade River
                                                             Quadrangle. USGS Open File Report 83-294.
                                                        Beikman, H.M. and Lathram, E.H. (1976) Preliminary Geologic Map of Northern Alaska.
                                                             USGS Miscellaneous Field Studies Map MF-789.

                                                        Remote Sensing Data
                                                        1) Meade River
                                                        NASA Color Infrared Aerial Photography: NASA/jSC 364, julv 1977
                                                             Roll 23, Frame Numbers: 46, 47@ 48, 49, 50, 51.
                                                        NASA Color Infrared Aerial Photography: Alaska 60 CIR, July 1979
                                                             Roll 2790, Frame Numbers: 3096      '3097, 3098, 3099, 3100, 3147, 4148, 3149, 3150,
                                                                                          3151, 3192, 3193, 3194, 3195, 3290, 3291, 3292.
                                                        U.S. Navv Black & White Aerial Photography: BAR, 1948-1949
                                                             Roil 22, Frame Numbers: 52, 53, 54, 77, 78, 79.
                                                             Roll 23, Frame Numbers: 91, 92, 93, 94, 95.
                                                             Roll 147, Frame Numbers:    11, 12, 13, 44, 45, 46.
                                                             Roll 175, Frame Numbers: 85, 86, 87, n4, 115, 116, 117.
                                                             Roll 181, Frame Numbers:    124, 125@ 126, 127, 128, 129.
                                                             Roll 197, Frame Numbers:    112, 113, 114@ 154, 155, 156, 157.
                                                             Roll 300, Frame Numbers:    194@195,196.
                                                             Roll 302, Frame Numbers:    154@155,156,157.

                                                        2) Usuktuk River
                                                        NASA Color Infrared Aerial Photography: Alaska 60 CIR, July 1979
                                                             Roll 2790, Frame Numbers: 3289, 3290, 3291, 3192.
                                                        U.S. Navv Black & White Aerial Photography: BAR, 1948-1949
                                                             Roil 147, Frame Numbers: 11, 12.

                                                                                                                                              105

                                        Appendix B: Sources of Mapping Data

                  Landsat Satellite Imagery Used for Map 2a
                  Date         Image Number         MSS Band
                  06/13/76         2508-21450            7
                  06/13/76         2508-21450            5
                  07/12/77         2902-21175            5
                  07/14/77         2904-21291            5
                  03/07/79        30367-2i4o4            7
                  05/02/79        30423-21502            7
                  06/05/79        30457-21401            7
                  05/16/81        22306-21372            7
                  05/29/83        40317-21422            4
                  05/16/84        50076-21342            7
                  06/01/84        50092-21344            7
                  06/08/84        50092-21410            7
                  06/08/84        50092-21410            5
                  06/15/84        50406-21472            7
                  06/17/84        50108-21350            7
                  06/17/84        50108-21350            5
                  07/01/84        50122-2 1473           7
                  07/01/84        50122-2 1473           5

                  Map 2b: Flood Hazard Potential of the Meade and Usuktuk Rivers

                  Maps
                  USGS 1:250,000 Topographic Map: Meade River Quadrangle
                  USGS 1:63,360 Topographic Maps: Meade River: A-2, A-3, B-2, B-3
                  Williams, John R. (1983) Engineering-Geologic Maps of Northern Alaska, Meade River
                       Quadrangle. USGS Open File Report 83-294.
                  Beikman, H.M. and Lathram, E.H. (1976) Preliminary Geologic Map of Northern Alaska.
                       USGS Miscellaneous Field Studies Map MF-789.

                  Remote Sensing Data
                  1) Meade River
                  NASA Color Infrared Aerial Photography: NASA/jSC 364, July 1977
                       Roll 23, Frame Numbers: 212, 21@, 298, 290, 291.
                  NASA Color Infrared Aerial Photography: Alaska 60 CIR, July 1979
                       Roll 2790, Frame Numbers: 3290, 3291, 3292, 3331, 3332, 3333.
                  NASA Color Infrared Aerial Photography: Alaska 60 CIR, July 1982
                       Roll 3101, Frame Numbers: 9620, 9621, 9622, 9714, 9715, 9716.
                  U.S. Navy Black & White Aerial Photographv: BAR, 1948-1949
                       Roll 147, Frame Numbers: 67, 68,69, 103, w4, 105, to6, 120, 121, 122, 123, 124, 183,
                                                184, 185.
                       Roll 148, Frame Numbers: 52, 53, 54@ 55, 66, 67, 68, 69, 71, 72@ 73.
                       Roll 244, Frame Numbers: 117, 118, 119, 120,
                       Roll 269, Frame Numbers: 6, 7, 8, 54, 55, 56.

                  106

                                                                            Appendix B: Sources of Mapping Data

                                                   Remote Sensing Data continued
                                                   2) Usuktuk River
                                                   NASA Color Infrared Aerial Photography: NASA/JSC 364, July 1977
                                                        Roll 23, Frame Numbers: 46, 47, 48, 49, 50, 51, 289, 290, 291, 292.
                                                   NASA Color Infrared Aerial Photography: Alaska 60 CIR, July 1979
                                                        Roll 2790, Frame Numbers: 3289, 3290, 3291, 3292, 3332, 3333, 3334.
                                                   Landsat Satellite Imagery Used for Map 2b
                                                   Date         Image Number         MSS Band
                                                   06/11/76          2506-2134o            7
                                                   06/13/76          2508-21450            7
                                                   06/13/76          2508-21450            5
                                                   07/12/77          2902-21175            5
                                                   07/14/77          2904-21291            5
                                                   03/07/79        30367-21404             7
                                                   05/02/79        30423-21520             7
                                                   06/05/79        30457-214ol             7
                                                   05/16/81        22306-21372             7
                                                   05/29/83        40317-21422             4
                                                   05/29/83        40317-21424             4
                                                   05/16/84        50076-21342             7
                                                   06/08/84        50099-21410             7
                                                   06/08/84        50099-21410             5
                                                   06/17/84        50108-21352             7
                                                   06/17/84        50108-21352             5
                                                   07/01/84        50122-21472             7
                                                   07/01/84        50122-21472             5

                                                   Map 2c: Flood Hazard Potential of the Meade River

                                                   Maps
                                                   USGS 1:250,000 Topographic Map: Lookout Ridge Quadrangle
                                                   USGS 1:63,360 Advance Proof Topographic Maps: Lookout Ridge: C-2, C-3
                                                   USGS 1:50,000 Advance Proof Topographic Maps: Lookout Ridge: D-2, D-3
                                                   Yeend, Warren (1983) Engineering-Geologic Maps of Northern Alaska, Lookout Ridge
                                                        Quadrangle. USGS Open File Report 83-279.
                                                   Beikman, H.M. and Lathtam, E.H. (1976) Preliminary Geologic Map of Northern Alaska.
                                                        USGS Miscellaneous Field Studies Map MF-789.

                                                   Remote Sensing Data
                                                   NASA Color Infrared Aerial Photography: NASA/JSC 264, July 1977
                                                        Roll 23, Frame Numbers: 212, 213.
                                                   NASA Color Infrared Aerial Photography: Alaska 60 CIR, July 1982
                                                        Roll 3101, Frame Numbers: 9643, 9644, 9645.
                                                   NASA Color Infrared Aerial Photography: Alaska 60 CIR, August 1982
                                                        Roll 3114, Frame Numbers: 923, 924, 925, 972, 973.

                                                                                                                                         107

                                       Appendix B: Sources of Mapping Data

                 Landsat Satellite Imagery
                 Date         Image Number       MSS Band
                 06/11/7116       2506-21340          7
                 05/02/7/9       3o423-2 1520         7
                 05/29/83        40317-21424          4
                 o6/17/84        50108-21352
                 06/17/84        50108-21352          5

                 Map 3: Flood Hazard Potential of the Kugrua River

                 Maps
                 USGS 1:250,000 Topographic Map: XVainwright Quadrangle
                 USGS 1:250,000 Topographic Map: Meade River Quadrangle
                 USGS 1:63,360 Topographic Maps: Wainwright: C-1, D-1
                                                  Meade River: B-5, C-5, D-5
                 Williams, John R. (1983) Engineering-Geologic Maps of Northern Alaska, Meade River
                       Quadrangle. USGS Open File Report 83-294.
                 Williams, John R. (1983) Engineering-Geologic Maps of Northern Alaska, Wainwright
                       Quadrangle. USGS Open File Report 83-457.
                 Beikinan, H.M. and Lathram, E.H. (1976) Preliminary Geologic Map of Northern Alaska.
                       USGS Miscellaneous Field Studies Map MF-789.

                 Remote Sensing Data
                 NASA Color Infrared Aerial Photography: NASA/jSC 364. July 1977
                       Roll 23, Frame Numbers: 58. 59, W 61.
                 NASA Color Infrared Aerial Photography: Alaska 60 CIR, Jul), 1979
                       Roll 2790. Frame Numbers: 3166, 3167, 3177, 3178, 3179, 3298, 3299.
                 U.S. Navv Black & White Aerial Photography: BAR, July 1949
                       Roil 171, Frame Numbers 1, 2, 3, 4, 5,'6, 7.
                 Landsat Satellite Imagery
                 Date         Image Number       MSS Band
                 06/13/76         2508-21450          7
                 06/13/76         2508-21450          5
                 07/14/77         2904-21291          5
                 05/02/ /9       30423-21520          7
                 07/01/84        50122-2 1473         7
                 07/01/84        50122-21473          5

                 Map 4a: Flood Hazard Potential of the Kuk and Ivisaruk Rivers

                 Maps
                 USGS 1:250,000 Topographic Map: WWainwright Quadrangle
                 USGS 1:63-360 Topographic Maps: Wainwright: B-1, 13-2@ B-3, C-1, C-2, C-3

                 108

                                                                         Appendix B: Sources of Mapping Data

                                                   Map 4a: continued
                                                   Williams, John R. (1983) E ngineering- Geologic Maps of Northern Alaska, Wainwright
                                                         Quadrangle. USGS Open File Report 83-457.
                                                   Beikman, H.M. and Lathram, E.H. (1976) Preliminary Geologic Map of Northern Alaska.
                                                         USGS Miscellaneous Field Studies Map MF-789.

                                                   Remote Sensing Data
                                                   1) Kuk River
                                                   NASA Color Infrared Aerial Photography: NASA/JSC 364, July 1977
                                                         Roll 23, Frame Numbers: 76, 77, 269, 270, 271, 272.
                                                   NASA Color Infrared Aerial Photography: Alaska 60 CIR, July 1979
                                                         Roll 2790, Frame Numbers: 3305, 3306, 3307.
                                                   NASA Color Infrared Aerial Photography: Alaska 60 CIR, August 1982
                                                         Roll 3088, Frame Numbers: 8649, 8650, 8651.
                                                   U.S. Navy Black & White Aerial Photography: BAR, 1948-1949
                                                         Roll 168, Frame Numbers: 201, 202.
                                                         Roll 330, Frame Numbers: 53, 54, 55.
                                                   2) Ivisaruk River
                                                   NASA Color Infrared Aerial Photography: NASA/JSC 364, July 1977
                                                         Roll 23, Frame Numbers: 78, 79, K 81.
                                                   Landsat Satellite Imagery
                                                   Date         Image Number        MSS Band
                                                   06/13/76          2508-21450         7
                                                   06/13/76          2508-21450         5
                                                   07/14/77          2go4-21291         5
                                                   05/02/79         30423-21520         7
                                                   07/01/84         50122-21473         7
                                                   07/01/84         50122-21473         5

                                                   Map 4b: Flood Hazard Potential of the Kuk, Ivisaruk and Kaolak Rivers.

                                                   Maps
                                                   USGS 1:250,000 Topographic Map: Wainwright Quadrangle
                                                   USGS 1:250,000 Topographic Map: Utukok River Quadrangle
                                                   USGS 1:63,360 Topographic Maps: Wainwright: A-2, A-3
                                                                                    Utukok River: D-3
                                                   USGS 1:50,000 Advance Proof Topographic Map: Utukok: D-2
                                                   Williams, John R. (1983) Engineering-Geologic Maps of Northern Alaska, Wainwright
                                                         Quadrangle. USGS Open File Report 83-457.
                                                   Beikman, H.M. and Lathram, E.H. (1976) Preliminary Geologic Map of Northern Alaska.
                                                         USGS Miscellaneous Field Studies Map MF-789.@

                                                                                                                                     log

                                           Appendix B; Sources of Mapping Data

                    Remote Sensing Data
                    1) Kuk River
                    NASA Color Infrared Aerial Photograph),: NASA/jSC 364. July 1977
                          Roll 23, Frame Numbers: 76, 77, 114, 115. 116.
                    U.S. Navy Black & White Aerial Photography: BAR, 1948-1949
                          Roll 315, Frame Numbers: 124, 125.

                    2) Ivisaruk River
                    NASA Color Infrared Aerial Photography: NASA/JSC 364, July 1977
                          Roll 23, Frame Numbers: 78,79,80,81, 110,111, 112, 113, 155, 156, 157, 158, 18T 188.

                    3) Kaolak River
                    NASA Color Infrared Aerial Photography: NASA/jSC 364, July 1977
                          Roll 23, Frame Numbers: 115, 116@ 117, 152, 153, 154, 190, 191, 192, 193, 194. 236,
                                                   23T 238.
                    U.S. Navy Black & White Aerial Photography: BAR, 1948-1949
                          Roll 315, Frame Numbers: 124, 125.
                    Landsat Satellite finagery Used for Map 4b
                    Date          Image Number         MSS Band
                    07/14/77           2904-21291            5
                    05/02/79          30423-21520            7
                    05/28/84          50088-21594            7

                    Map 4c: Flood Hazard Potential of the Avalik and Ketik Rivers

                    Maps
                    USGS  1:250,000 Topographic Map: Wainwright Quadrangle
                    USGS  1:250,000 Topographic Map: Meade River Quadrangle
                    USGS 1:250,000 Topographic Map: Utukok River Quadrangle
                    USGS  1:250,000 Topographic Map: Lookout Ridge Quadrangle
                    USGS  1:63,360 Topographic Maps: Wainwright: A-1, A-2
                                                       Meade River: A-4, A-5
                    USGS  1:50,000 Advance Proof Topographic Maps: Utukok River: D-1, D-2
                                                                       Lookout.Ridge: D-4, D-5
                    Williams, John R. (1983) Engineering-Geologic Maps of Northern Alaska, Meade River
                          Quadrangle. USGS Open File Report 83-294.
                    Williams, John R. (1983) Engineering-Geologic Maps of Northern Alaska, Wainwright
                          Quadrangle. USGS Open File Report 83-457.
                    Beikman, H.M. and Lathram, E.H. (1976) Preliminary Geologic Map of Northern Alaska.
                          USGS Miscellaneous Field Studies Map MF-789.

                    110

                                                                            Appendix B: Sources of Mapping Data

                                                    Remote Sensing Data
                                                    1) A-,,,alik River
                                                    NASA Color Infrared Aerial Photography: NASA/JSC 364, July 1977
                                                          Roll 23, Frame Numbers: 115, 11(;, 117, 118, 144, 145, 146, 147, 148, 201, 202, 203,
                                                                                    2o4,205,2o6.
                                                    NASA Color Infrared Aerial Photography: Alaska 60 CIR, July 1982
                                                          Roll 3101, Frame Numbers: 9637, 9638@ 9639.
                                                    U.S. Navy Black & White Aerial Photography: BAR, 1948-1949
                                                          Roll 315, Frame Numbers: 124, 125, 126@ 127.
                                                    2) Ketik River
                                                    NASA Color Infrared Aerial Photography: NASA/JSC 364, July 1977
                                                          Roll 23, Frame Numbers: 115, 116, 117, 149, 150, 151, i957 196, 232, 233.
                                                    NASA Color Infrared Aerial Photography: NASA/JSC 264. August 1977
                                                          Roll 25, Frame Numbers: 251, 20, 253, 291, 292@ 293.
                                                    U.S. Navy Black & White Aerial Photography: BAR, 1948-1949
                                                          Roll 315, Frame Numbers: 125, 126, 127.
                                                    Landsat Satellite Imagery Used for Map Ic
                                                    Date          Image Number         MSS Band
                                                    07/14/77            2904-21291           5
                                                    05/02/79         30423-2 1520            7
                                                    05/29/83          40317-21424            4

                                                    Map 4d: Flood Hazard Potential of the Ketik River

                                                    Maps
                                                    USGS 1:250,000 Topographic Map: Utukok River Quadrangle
                                                    USGS 1:63,360 Topographic Maps: Utukok River: C- I
                                                    USGS 1:50,000 Advance Proof Topographic Maps: Utukok River: C-2, D-1, D-2
                                                    Williams, John R. (1983) Engineering-Geologic Maps of Northern Alaska. Wainwright
                                                          Quadrangle. USGS Open File Report 83-457.
                                                    Williams, John R. and Others (1977) Preliminary Surficial Deposits Map of NPR-A. USGS
                                                          Open File Report 77-868.
                                                    Beikman. H.M. and Lathram, E.H. (1976) Preliminary Geologic Map of Northern Alaska.
                                                          USGS Miscellaneous Field Studies Map MF-789.

                                                    Remote Sensing Data
                                                    NASA Color Infrared Aerial Photography: NASA/JSC 364, July 1977
                                                          Roll 23, Frame Numbers: 232, 233.
                                                    NASA Color Infrared Aerial Photography: NASA/jSC 364, August 191/ 7
                                                          Roll 25, Frame Numbers: 251. 252,   253, 291. 292, 293.

                                         Appendix B: Sources of Mapping Data

                  Landsat Satellite Imagery
                  Date          Image Number        MSS Band
                  04/28/84          50088-21594           7

                  Map 5: Flood Hazard Potential of the Tunalik, Ongorakvik and Nokotlek Rivers

                  Maps
                  USGS 1:250,000 Topographic Map: Wainwright Quadrangle
                  USGS 1:63,360 Topographic Maps: Wainwright: A-3, A-4, A-5, B-3, B-4, B-5, B-6
                  Williams, John R. (1983) Engineering- Geologic Maps of Northern Alaska, Wainwright
                        Quadrangle. USGS Open File Report 83-457.
                  Beikman, H.M. and Lathram, E.H. (1976) Preliminary Geologic Map of Northern Alaska.
                        USGS Miscellaneous Field Studies Map 14F-789.

                  Remote Sensing Data
                  1) Tunalik River
                  NASA Color Infrared Aerial Photography: NASA/jSC 364, July 1977
                        Roll 23, Frame Numbers: 90, 91, 101, 102, 103, 104, 105.
                  U.S. Navy Black & White Aerial Photography: BAR, August 1948
                        Roll 3 6, Frame Numbers: 15 5, 15 6, 15 7.
                        Roll 37, Frame Numbers: 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125.
                  2) Ongorakvik River
                  NASA Color Infrared Aerial Photography: NASA/JSC 364, July 1977
                        Roll 23, Frame Numbers: 84, 85, 86, 106, 107, 263, 264.
                  U.S. Navy Black & White Aerial Photography: BAR, August 1948, July 1949
                        Roll 36, Frame Numbers: 15, 16, 17, 64, 65, 93, 94.
                        Roll 335, Frame Numbers: 30, 31, 32.
                  3) Nokotlek River
                  NASA Color Infrared Aerial Photography: NASA/JSC 364, July 1977
                        Roll 23, Frame Numbers: 83, 84, 85, 107, 108, 109, 263, 264.
                  U.S. Navy Black & White Aerial Photographv: BAR, August 1948, July 1949
                        Roll 36, Frame Numbers: 18, 19, 59, 60, 99, 100.
                        Roll 335, Frame Numbers: 27, 28@ 29.
                  Landsat Satellite Imagery Used for Map 5
                  Date          Image Number        MSS Band
                  06/13/76           2508/21450           7
                  06/13/76           2508-21450           5
                  07/14/77           2904-21291           5
                  05/02/79          30423-21520           7

                  112

                                                                           Appendix C. River Channel Profile Data

                                                     lkpikpuk River channel profile data from Smith Bay

                                                           Channel Length                 Elevation of                   Gradient
                                                          Measured (miles)               Channel (feet)                (feet per mile)
                                                                  25.0                          10.0                         o.4
                                                                  36.0                          25.0                         1.4
                                                                  42.5                          50.0                         3.9
                                                                  48.0                          5 7 - 0                      1.3
                                                                  85.4                          65.6                         0.2
                                                                  98.0                          98.4                         2.6
                                                                 105.5                        131.2                          4.4
                                                                 151.3                        1 64.o                         0.7
                                                                 156.o                        180.4                          3.5
                                                                 162.7                        196.8                          2.5
                                                                 181.3                        213.3                          0.9

                                                     Average channel gradient is 1.2 ft./nii.
                                                     Data from USGS topographic maps; secappendix B.

                                                     Meade River channel profile data from Admiralty Bay

                                                           Channel Length                 Elevation of                   Gradient
                                                          Measured (miles)               Channel (feet)                (feet per mile)
                                                                  60.5                          25.0                         o.4
                                                                  99.2                          65.6                         1.0
                                                                 111.0                          98.4                         2.8
                                                                 119.3                        131.2                          4.0
                                                                 145.9                        164.o                          1.2
                                                                 150.4                        200.0                          8.0

                                                     Average channel gradient is 1.3 ft./Ini.
                                                     Data from USGS topographic maps; see appendix B.

                                                     Usuktuk River channel profile data from the junction with the Meade River

                                                           Channel Length                 Elevation of                   Gradient
                                                          Measured (miles)               Channel (feet)                (feet per mile)
                                                                 97.0                         50.0                           0.26

                                                     Average channel gradient is 0.26 ft./mi.
                                                     Data from USGS topographic maps; see appendix B.

                                                                                                                                         113

                                             Appendix C. River Channel Profile Data

                    Alaktak River channel profile data from Pittalukruak Lake

                           Channel-Length                    Elevation of                       Gradient
                          Measured (miles)                   Channel (feet)                 (feet per mile)
                                   34.5                           10.0                              0.3
                                   43.5                           25.0                              1.7

                    A-,,crage channel gradient is 0.6 ft./mi.
                    Data from USGS topographic maps; see appendix 13-

                    Chipp/Oumalik River channel profile data from Admiralty Bay

                                          Channel Length                    Elevation of                       Gradient
                                         Measured (miles)                  Channel (feet)                   (feet per mile)
                      Chipp R.                    11.0                            10.0                             0.9
                                                  35.0                            25-0                             0.6
                                                  50.0                            50.0                             1.7
                                                  62.0                            57.0                             o.6
                    Oumalik R.                   102.0                            75.0                             0.5

                                   Average channel gradient of the Chipp Ri%,er is 0.9 ft./mi.
                                   Average channel gradient of the Otimalik RiN7er is 0.5 ft./mi.
                                   Data from USGS topographic maps; see appendix B.

                    Kuk/Avalik River channel profile data from the Chukchi Sea

                          Channel Length                     Elevation of                      Gradient
                          Measured (miles)                   Channel (feet)                 (feet per mile)
                                   53.0                           25.0                              0.5
                                   74.6                           32.8                              0.4
                                  7 9.77                          49.2                              3.2
                                   85.2                           65.6                              3.0
                                  104.9                           98.4                              1.7

                    Average channet gradient is 0.9 ft./mi.
                    Data from USGS topographic niaps@ see appendix B.

                    114

                                                                            Appendix C. River Channel Profile Data

                                                     Topagoruk River channel profile data from Admiralty Bay

                                                           Channel Length                   Elevation of                     Gradient
                                                           Measured (miles)                 Channel (feet)                (feet per mile)
                                                                   20.0                           12.0                            0.6
                                                                   33.5                           25.0                            1.0
                                                                   51-5.                          50.0                            1.4
                                                                   54.o                           75.0                            10.0
                                                                   101.5                          100.0                           0.5

                                                     Average channel gradient is 1.0 ft./mi.
                                                     Data from USGS topographic maps; see appendix B.

                                                     Ketik River channel profile data from the junction with the Avalik River

                                                           Channel Length                   Elevation of                     Gradient
                                                           Measured (miles)                 Channel (feet)                (feet per mile)
                                                                   13.5                           32.8                            2.4
                                                                   25.3                           49.2                            1.4
                                                                   41.5                           65.6                            1.0
                                                                   60.8                           98.4                            1.7

                                                     Average channel gradient is 1.6 ft./mi.
                                                     Data from USGS topographic maps; see appendix-B.

                                                     Ivisaruk River channel profile data from the junction with the Kuk River

                                                           Channel Length                   Elevation of                     Gradient
                                                           Measured (miles)                 Channel (feet)                (feet per mile)
                                                                   46.5                           25.0                            0.5
                                                                   51.0                           50.0                            5.6
                                                                   56.o                           100.0                           10.0

                                                     Average channel gradient is 1.8 ft./mi.
                                                     Data from USGS topographic maps; see appendix B.

                                                     Kugrua River channel profile data from Kugrua Bay

                                                           Channel Length                   Elevation of                     Gradient
                                                           Measured (miles)                 Channel (feet)                (feet per mile)
                                                                   18.5                           25.0                            1.4
                                                                   24.0                           50.0                            4.5
                                                                   39.0                           75.0                            1 /7

                                                     Average channel gradient is 1.9 ft./mi.
                                                     Data from USGS topographic maps; see appendix B.

                                                                                                                                                 115

                                          Appendix C. River Channel Profile Data

                   Kaolak River channel profile data from the junction with the Avalik River

                          Channel Length                   Elevation of                     Gradient
                          Measured (miles)                 Channel (feet)                (feet per mile)
                                 13.5                           49.2                            3.6
                                 26.1                           65.6                            L3
                                 43-7/                          98.4                            0.9

                   Average channel gradient is 2.3 ft./mi.
                   Data from USGS topographic maps; see appendix B.

                   Nokotlek River channel profile data from Kasegaluk Lagoon

                          Channel Length                   Elevation of                     Gradient
                          Measured (miles)                 Channel (feet)                (feet per mile)
                                 10.5                           25.0                            2.4
                                 18.0                           50.0                            3.3

                   Average channel gradient is 2.8 ft./mi.
                   Data from USGS topographic maps; see appendix B.

                   Tunalik River channel profile data from Avak Inlet

                          Channel Length                   Elevation of                     Gradient
                          Measured (miles)                 Channel (feet)                (feet per mile)
                                   6.o                          25.0                            4.2
                                   7.5                          50.0                            16.7
                                 22.5                           75.0                            1.7
                                 27.5                           100.0                           5.0

                   Average channel gradient is 3.6 ft./mi.
                   Data from USGS topographic maps; see appendix B.

                   Ongorakvik River channel profile data from Kasegaluk Lagoon

                          Channel Length                   Elevation of                     Gradient
                          Measured (miles)                 Channel (feet)                (feet per mile)
                                 11.5                           25.0                            2.2
                                 13.0                           50.0                            16.7
                                 15.0                           75.0                            12.5
                                 16.5                           100.0                           16.7

                   Average channel gradient is 6.1 ft./mi.
                   Data from USGS topographic maps; see appendix B.

                   116

                                                                            Appendix D. Active Channel Material Samples

                                                        Map Ic, lkpikpuk Active Channel material Sample (A.C.M.S.) No. I

                                                        A representative material sample taken from an actiN,e channel bar.
                                                        Gradation Test (AASHTO T87-70 and T88-70)

                                                               Sieve Mesh No.                 Sieve Aperture                     % Passing
                                                                        ill                       25.4   rum                          98.7 ,
                                                                        V2                        12.7   mm                           85.0
                                                                        4                         4.75   mm                           49.2
                                                                        10                        2.0    nim                          49.2
                                                                        4o                        0.425 mm                            8.9
                                                                      200                         0.075 mm                            1.3

                                                        Map 1c, lkpikpuk Active Channel Material Sample (A.C.M.S.) No. 2

                                                        A representatiN,e material sample taken from an active channel bar.
                                                        Gradation Test (AASHTO T87-70 and T88-70)

                                                              Sieve Mesh No.                  Sieve Aperture                     % Passing
                                                                        ill                       25.4   mm                           100.0
                                                                        112                       12.7   mm                           98.0
                                                                        4                         4.75   mm                           72.0
                                                                        10                        2.0    mm                           37.5
                                                                        40                        0.425 mm                            13.3
                                                                     200                          0.075 mm                            0.3

                                                        Note: The channel material downstream of the junctions of the lkpikpuk, Price and
                                                              TitalUk Rivers is fine to medium sand.

                                                                                                                                                  117

                            7

                  Figure D-1.
                  lkpikpuk Active Channel Material Sample site (A.C.M. S.) No. I (Map I c). A representative
                  material sample taken from an active channel bar. The scale bar is in inche's and centimeters.

                  118

                                                   W

                                                       Figure D-2.
                                                       Ikpikpuk Active Channel Material Sample site (A.C.M.S.) No. 2 (Map I c). A representative
                                                       material sample taken from an active channel bar. The scale bar is in inches and centimeters.

                                                                                                                                              119

                                      Appendix D. Active Channel Material Samples

                   Map lb, Topagoruk Active Channel Material Sample (A.C.M.S.) No. 1

                   A representative material sample taken from an active channel bar.
                   Gradation Test (AASHTO T87-70 and T88-70)

                         Sieve Mesh No.                Sieve Aperture                    % Passing
                                  V                       25.4    mm                        100.0
                                 '12                      12.7    mm                        100.0
                                  4                        4.75   mm                        100.0
                                 10                        2.0    mm                        100.0
                                 4o                        0.425 mm                           99.2
                                200                        0.075 mm                           5.3

                                                                                                                                               7-

                                                                                          Ave,
                                                                                       _Ff,          Lit P,

                                                                                                                       SeR
                                                      @;iiv! 1'14_4@2
                                                                                                                      M "k
                                                           ax
                                                                                                   Un
                                                                                                   -k A
                                                                                                                                     4ffl
                                                              -IN
                                                                                            @-4

                                                                                                                   F- mxi,
                                                                                                  @,E
                                                                                              %

                                                                                                         W       - - - - - - - - - -

                   Figure D-3.
                   Topagoruk Active Channel Material Sample site (A.C.M.S.) No. I (Map lb). A representative
                   material sample taken from an active channel bar. The scale bar is in inches and centimeters.

                   120

                                                                               Appendix D. Active Channel Material Samples

                                                          Map 2b, Meade Active Channel Material Sample (A.C.M.S.) No. I

                                                          A representative material sample taken from an active channel bar.
                                                          Gradation Test (AASHTO T87-70 and T88-70)

                                                                 Sieve Mesh No.                  Sieve Aperture                      % Passing
                                                                          V                         25.4     mm                          100.0
                                                                         1/21,                       12.7    mm                           97.3
                                                                           4                          4.75   turn                         82.2
                                                                         10                           2.0    mm                           47.3
                                                                         40                           0.425 mm                              7.7
                                                                        200                           0.075 mm                              0.6

                                                          Map 2b, Meade Active Channel Material Sample (A.C.M.S.) No. 2

                                                          No sample was taken at this site. Material is fine to medium sand with small pebble sized
                                                          pieces of coal.

                                                                                                 ra,@N,

                                                          Figure D-4.
                                                          Meade Active Channel Material Sample site (A.C.M.S.) No. I (Map 2b). A representative
                                                          material sample taken from an active channel bar. The scale bar is in inches and centimeters.

                                                                                                                                                        121

                                                                    n
                                                                40
                                                             n- - vo,
                                                             7
                           5;@ @-P

                                                                               41-

                  Figure D-5.
                  Meade Active Channel Material Sample site (A.C.M.S.) No. 2 (Map 2b). No sample was taken
                  at this site. The river's bed load material is fine to medium sand with small pebble sized
                  pieces of coal. The scale bar is in inches and centimeters.

                  122

                                                                          Appendix D. Active Channel Material Samples

                                                       Map 4b, Ivisaruk Active Channel Material Sample (A.C.M.S.) No. I

                                                       A representative material sample taken from an active channel bar.
                                                       Gradation Test (AASHTO T87-70 and T88-70)

                                                             Sieve Mesh No.                 Sieve Aperture                    % Passing
                                                                      V,                       25.4 rum                          98.1
                                                                       4                        4.75 rum                         6o.2
                                                                      10                        2.0     nim                      42.1
                                                                      40                        0.425 turn                       34.5
                                                                    200                         0.075 mm                           2.5

                                                     I,-  -17M

                                                                                        r

                                                       Figure D-6.
                                                       Ivisaruk Active Channel Material Sample site (A.C.M.S.) No. I (Map 4b). A representative
                                                       material sample taken from an active channel bar. The scale bar is in inchesand centimeters.

                                                                                                                                              123

                                      Appendix D. Active Channel Material Samples

                   Map 5, Material Site (M.S.) No. 1

                   A representative sample taken from an Mb, deposit related to a Pelukian shoreline adja-
                   cent to the channel of the Ongorakvik River.
                   Gradation Test (AASHTO T87-70 and T88-70)

                         Sieve Mesh No.                 Sieve Aperture                   % Passing
                                  V,                       25.4     mm                       98.1
                                   4                        4.75 mm                          60.2
                                  10                        2.0 mm                           42.1
                                  40                        0.425 mm                         34.5
                                200                         0-07 5 mm                          2.5

                   Note: Fines are available at this site from a 2 ft. thick laver of silt and organic matter
                         (roots) that overlie the deposit.

                   124

                                                                                                      N,

                                                       FigUre D-7.
                                                       Material Site (M.S.) No. I (Map 5). A representative sample taken froman Mb, deposit related
                                                       to a Pelukian shoreline adjacent to the channel of the Ongorakvik River. The scale bar is in
                                                       inches and centimeters. See also FigUre D-8.

                                                                                                                                              125

                                                                                                                    T
                                                                                                                     h7 'MW,

                  Figure D-8.
                  Looking South along the Mb, deposit of Material Site (,'vI.S.) No. I (Map 5). Notice the two
                  foot thick layer of silt and organic matter (right middle ground) that overlies the sand and
                  gravel of the deposit (center).

                  126

                                                                                   Appendix E. List of Map Units

                                                       Map I a: Flood Hazard Potential of the Ikpikpuk, Chipp, Alaktak, Migualkiak,
                                                                Piasuk and Topagoruk Rivers.

                                                       Potential Flood Hazard Units
                                                       I    Low magnitude-high frequency flooding. Includes talik lakes connected to active
                                                            river channels.
                                                       2    Intermediate magnitude-intermediate frequency flooding.
                                                       3    High magnitude-low frequency flooding.
                                                       4    Rarely floods. Very high magnitude-very low frequency flooding. May contain
                                                            areas that do not flood.
                                                       5    No flooding.
                                                       6    High floodplain terrace or eolian dune on the floodplain; no flooding.
                                                       Fd   Fluvial delta deposits, subject to ocean storm surge flooding.

                                                       Terrain Units

                                                       L    Talik take.
                                                       Lt   Thaw-lake (talik) and thaw-lake deposits; non-flood unit.
                                                       Es   Eolian sand; non-flood unit.
                                                       Mc   Marine sand; non-flood unit.
                                                       Mf   Marine silt and clay; non-flood unit.
                                                       F    Fluvial deposits; non-flood unit.
                                                       Fd   Fluvial delta deposits, subject to ocean storm surge flooding.

                                                       Map I b: Flood Hazard Potential of the lkpikpuk, Chipp, Oumalik and Topa-
                                                                goruk Rivers.

                                                       Potential Flood Hazard Units
                                                       I    Low magnitude-high frequency flooding.
                                                       2    Intermediate magnitude-intermediate frequency flooding.
                                                       3    High magnitude-low frequency flooding.
                                                       4    Rarely floods. Very high magnitude-very low frequenq flooding.
                                                       5    No flooding.
                                                       6    High floodplain terrace or eolian dune on the floodplain; no flooding.
                                                       7    Very high floodplain terrace, no flooding.
                                                       Fpm  Undifferentiated floodplain of meandering river. Contains both flooding and non-
                                                            flooding areas.

                                                                                                                                             127

                                               Appendix E. List of Map Units

                     Terrain Units

                     L   Talik lake.
                     Lt  Thaw-lake (talik) and thaw-lake deposits; non-flood unit.
                     Es  Eolian sand; non-flood unit.
                     Elx Upland silt; non-flood unit.
                     Fpm Meander floodplain.

                     Map lc: Flood Hazard Potential of the Ikpikpuk River.

                     Potential Flood Hazard Units
                     I   Low magnitude-high frequency flooding.
                     2   Intermediate magnitude-intermediate frequency flooding.
                     3   High magnitude-low frequency flooding.
                     4   Rarely floods. Very high magnitude-very low frequency flooding.
                     5   No flooding.
                     6   High floodplain terrace, no flooding.
                     7   Very high floodplain terrace, no flooding.
                     Fpm Undifferentiated floodplain of meandering river. Contains both flooding and non-
                         flooding areas.

                     Terrain Units

                     L   Talik lake.
                     Lt  Thaw-lake (talik) and thaw-lake deposim non-flood unit.
                     Es  Eolian sand; non-flood unit.
                     EIx Upland silt; non-flood unit.
                     Fsa Sandy retransported deposits; non-flood unit.
                     Fpm Meander floodplain.

                     Map I d: Flood Hazard Potential of the Ikpikpuk River.

                     Potential Flood Hazard Units
                     I   Low magnitude-high frequency flooding.
                     2   Intermediate magnitude-intermediate frequency flooding.
                     3   High magnitude-low frequency flooding.
                     4   Rarely floods. Very high magnitude-very low frequencv flooding.

                     128

                                                                                   Appendix E. List Of Map Units

                                                        Map 1d: continued

                                                        6    High floodplain terrace, no flooding.
                                                        7    Very high floodplain terrace, no flooding.
                                                        Fprn Undifferentiated floodplain of meandering river. Contains both flooding and non-
                                                             flooding areas.

                                                        Terrain Units

                                                        L    Talik lake.
                                                        Lt   Thaw-lake (talik) and thaw-lake deposits; non-flood unit.
                                                        Etx  Upland silt@ non-flood unit.
                                                        Fsa  Sandi, retransported deposits; non-flood unit.
                                                        Fpm  Meander floodplain.
                                                        Bx   Unditerentiated bedrock.

                                                        Map 2a. Flood Hazard Potential of the Meade and Usuktuk Rivers.

                                                        Potential Flood Hazard Units
                                                        I    Low magnitude-high frequency flooding.
                                                        2    Intermediate magnitude- intermediate frequency flooding.
                                                        3    High magnitude-low frequency flooding.
                                                        4    Rarely floods. Very high magnitude-very low frequency flooding.
                                                        5    No flooding,
                                                        6    High floodplain terrace or volian dune on the floodplain; no flooding.

                                                        Terrain Units

                                                        L    Talik lake.
                                                        Lt   Thaw-lake (talik) and thaw-lake deposits; non-flood unit.
                                                        Es   Eolian sand; non-flood unit.
                                                        Mc   Marine sand: non-flood unit.

                                                        Maps 2b and 2c: Flood Hazard Potential of the Meade and Usuktuk Rivers.

                                                        Potential Flood Hazard Units
                                                        I    Low magnitude-high frequency flooding,
                                                        2    Intermediate magnitude-intcrmediate frequency flooding.

                                                                                                                                             129

                                            Appendix E. List of Map Units

                  Maps 2b and 2c: continued
                  3    High magnitude-low frequency flooding.
                  4    Rarely floods. Very high magnitude-very low frequency flooding.
                  5    No flooding.
                  6    High floodplain terrace or eolian dune on the floodplain; no flooding.
                  Fpm  Undifferentiated floodplain of meandering river. Contains both flooding and non-
                       flooding areas.

                  Terrain Units

                  L    Talik lake.
                  Lt   Thaw-lake (talik) and thaw-lake deposits; non-flood unit.
                  Es   Eolian sand; non-flood unit.
                  EIx  Upland silt; non-flood unit.
                  Fpm  Meander floodplain.
                  Kn   Bedrock.

                  Map 3: Flood Hazard Potential of the Kugrua River.

                  Potential Flood Hazard Units
                  I    Low magnitude-high frequency flooding.
                  2    Intermediate magnitude-intermediate frequency flooding.
                  3    High magnitude-low frequency flooding.

                  Terrain Units

                  L    Talik lake.
                  Lt   Thaw-lake (talik) and thaw-lake deposits; non-flood unit.
                  Mc   Marine sand; non-flood unit.
                  Mb   Marine beach, bar and spit deposits; subject to ocean storm surge flooding.
                  Mb@  Pelukian shoreline marine beach, offshore bar and barrier island deposits; non-
                       flood units.

                  Map 4a: Flood Hazard Potential of the Kuk and lvisaruk Rivers.

                  Potential Flood Hazard Units
                  I    Low magnitude-high frequency flooding. Includes talik lakes connected to active
                       river channels.

                  130

                                                                           Appendix E. List of Map Units

                                                  Map 4a: continued
                                                  2    Intermediate magnitude-intermediate frequency flooding.
                                                  3    High magnitude-low frequency flooding.
                                                  4    Very high magnitude-very low frequency flooding.
                                                  5    High floodplain terrace, no flooding.

                                                  Terrain Units

                                                  L    Talik lake.
                                                  Lt   Thaw-lake (talik) and thaw-take deposits; non-flood unit.
                                                  Mc   Marine sand; non-flood unit.
                                                  Mb   Marine beach, bar and spit deposits; subject to ocean storm surge flooding.
                                                  Mb,  Pelukian shoreline marine beach, offshore bar and barrier island deposits; non-
                                                       flood unit.

                                                  Map 4b: Flood Hazard Potential of the Kuk, lvisaruk and Kaolak Rivers.

                                                  Potential Flood Hazard Units
                                                  I    Low magnitude-high frequency flooding.
                                                  ?    Intermediate magnitude-intermediate frequency flooding.
                                                  3    High magnitude-low frequency flooding.
                                                  4    Rarely floods. Very high magnitude-very low frequency flooding.
                                                  5    High floodplain terrace, no flooding.

                                                  Terrain Units

                                                  L    Talik lake.
                                                  Lt   Thaw-lake (talik) and thaw-lake deposits; non-flood unit.
                                                  Mc   Marine sand; non-flood unit.
                                                  Elx  Upland silt; non-flood unit.
                                                  Kn   Bedrock.

                                                  Map 4c: Flood Hazard Potential of the Avalik and Ketik Rivers.

                                                  Potential Flood Hazard Units
                                                  I    Low magnitude-high frequency flooding.
                                                  2    Intermediate magnitude-intermediate frequency flooding.

                                                                                                                                 131

                                           Appendix E. List of Map Units

                  Map 4c: continued
                  3    High magnitude-low frequency flooding.
                  4    Rarely floods. Very high magnitude-very low frequency flooding.
                  5    High floodplain terrace, no flooding.

                  Terrain Units

                  L    Talik lake.
                  Lt   Thaw-lake (talik) and thaw-lake deposits; non-flood unit.
                  Me   Marine sand; non-flood unit.
                  EIx  Upland silt; non-flood unit.
                  Kn   Bedrock.

                  Map 4d: Flood Hazard Potential of the Ketik River.

                  Potential Flood Hazard Units
                  I    Low magnitude-high frequency flooding.
                  2    Intermediate magnitude-intermediate frequency flooding.
                  3    High magnitude-low frequency flooding.
                  4    Rarely floods. Very high magnitude-verv low frequencv flooding.
                  5    High floodpalin terrace, no flooding.

                  Terrain Units
                  Lt   Thaw-lake (talik) and thaw-lake deposits; non-flood unit.
                  Elx Upland silt; non-flood unit.
                  Kn   Bedrock.

                  Map 5: Flood Hazard Potential of the Tunalik, Ongorakvik and Nokotlek Rivers.

                  Potential Flood Hazard Units
                  I    Low magnitude-high frequency flooding.
                  2    Intermediate magnitude-intermediate frequency flooding.
                  3    High magnitude-low frequency flooding.

                  132

                                                                                Appendix E. List of Map Units

                                                     Terrain Units

                                                     L     Talik take.
                                                     Lt    Thaw-take (talik) and thaw-lake deposits; non-flood unit.
                                                     Mc    Marine sand; non-flood unit.
                                                     Elx   Upland silt; non-flood unit.
                                                     Mb    Marine beach, bar and spit deposits; subject to ocean storm surge flooding.
                                                     Mb,   Pelukian shoreline marine beach, offshore bar and barrier island deposits; non-
                                                           flood unit.
                                                     Mb,   Pre-Illinoian or Kotzebuan shoreline marine beach. offshore bar and barrier island
                                                           deposits; non-flood unit.

                                                                                                                                         133

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